397453921 has 4 divisors (see below), whose sum is σ = 398115844. Its totient is φ = 396792000.

The previous prime is 397453919. The next prime is 397453933. The reversal of 397453921 is 129354793.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 367258896 + 30195025 = 19164^2 + 5495^2 .

It is a cyclic number.

It is not a de Polignac number, because 397453921 - 2¹ = 397453919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (397453321) 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, 330060 + ... + 331261.

It is an arithmetic number, because the mean of its divisors is an integer number (99528961).

Almost surely, 2^397453921 is an apocalyptic number.

It is an amenable number.

397453921 is a deficient number, since it is larger than the sum of its proper divisors (661923).

397453921 is an equidigital number, since it uses as much as digits as its factorization.

397453921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661922.

The product of its digits is 204120, while the sum is 43.

The square root of 397453921 is about 19936.2464120004. The cubic root of 397453921 is about 735.2396651595.

The spelling of 397453921 in words is "three hundred ninety-seven million, four hundred fifty-three thousand, nine hundred twenty-one".