397991057 has 4 divisors (see below), whose sum is σ = 415295040. Its totient is φ = 380687076.

The previous prime is 397991039. The next prime is 397991071. The reversal of 397991057 is 750199793.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 750199793 = 7 ⋅107171399.

It is not a de Polignac number, because 397991057 - 2⁶ = 397990993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 397990996 and 397991014.

It is not an unprimeable number, because it can be changed into a prime (397990057) 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, 8651957 + ... + 8652002.

It is an arithmetic number, because the mean of its divisors is an integer number (103823760).

Almost surely, 2^397991057 is an apocalyptic number.

It is an amenable number.

397991057 is a deficient number, since it is larger than the sum of its proper divisors (17303983).

397991057 is a wasteful number, since it uses less digits than its factorization.

397991057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17303982.

The product of its (nonzero) digits is 535815, while the sum is 50.

The square root of 397991057 is about 19949.7132059586. The cubic root of 397991057 is about 735.5707273698.

The spelling of 397991057 in words is "three hundred ninety-seven million, nine hundred ninety-one thousand, fifty-seven".