Properties of the Number 397

Three Hundred Ninety-Seven

Basics

Value: 396 → 397 → 398

Parity: odd

Prime: Yes

Previous Prime: 389

Next Prime: 401

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 397

Divisors: 1, 397

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 110001101

Octal: 615

Duodecimal: 291

Hexadecimal: 18d

Square: 157609

Square Root: 19.924858845171276

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Pythagorean primes: primes of the form 4·k + 1. A2144

Hex (or centered hexagonal) numbers: 3·n*(n+1)+1 (crystal ball sequence for hexagonal lattice). A3215

Primes of the form 6m + 1. A2476

Primes p such that p + 4 is also prime. A23200

Primes congruent to 1 or 2 modulo 4; or, primes of form x² + y²; or, -1 is a square mod p. A2313

Number of inseparable partitions of n; see Comments. A325535

Primes congruent to 1 (mod 12). A68228

Primes p such that (p+1)/2 is prime. A5383

Number of fractions in Farey series of order n. A5728

Single (or isolated or non-twin) primes: Primes p such that neither p-2 nor p+2 is prime. A7510