397229921 has 4 divisors (see below), whose sum is σ = 433341744. Its totient is φ = 361118100.

The previous prime is 397229893. The next prime is 397229923. The reversal of 397229921 is 129922793.

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.

It is a cyclic number.

It is not a de Polignac number, because 397229921 - 2¹⁸ = 396967777 is a prime.

It is a super-2 number, since 2×397229921² = 315583220275332482, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (397229923) 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, 18055895 + ... + 18055916.

It is an arithmetic number, because the mean of its divisors is an integer number (108335436).

Almost surely, 2^397229921 is an apocalyptic number.

It is an amenable number.

397229921 is a deficient number, since it is larger than the sum of its proper divisors (36111823).

397229921 is a wasteful number, since it uses less digits than its factorization.

397229921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36111822.

The product of its digits is 122472, while the sum is 44.

The square root of 397229921 is about 19930.6277121419. The cubic root of 397229921 is about 735.1015152795.

The spelling of 397229921 in words is "three hundred ninety-seven million, two hundred twenty-nine thousand, nine hundred twenty-one".