397931 has 4 divisors (see below), whose sum is σ = 399912. Its totient is φ = 395952.

The previous prime is 397921. The next prime is 397939. The reversal of 397931 is 139793.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 139793 = 43 ⋅3251.

It is a cyclic number.

It is not a de Polignac number, because 397931 - 2⁶ = 397867 is a prime.

It is a super-2 number, since 2×397931² = 316698161522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (397939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 650 + ... + 1103.

It is an arithmetic number, because the mean of its divisors is an integer number (99978).

2³⁹⁷⁹³¹ is an apocalyptic number.

397931 is a deficient number, since it is larger than the sum of its proper divisors (1981).

397931 is a wasteful number, since it uses less digits than its factorization.

397931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1980.

The product of its digits is 5103, while the sum is 32.

The square root of 397931 is about 630.8177232767. The cubic root of 397931 is about 73.5533726209.

The spelling of 397931 in words is "three hundred ninety-seven thousand, nine hundred thirty-one".