231021397 has 4 divisors (see below), whose sum is σ = 231427980. Its totient is φ = 230614816.

The previous prime is 231021389. The next prime is 231021409. The reversal of 231021397 is 793120132.

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 11566801 + 219454596 = 3401^2 + 14814^2 .

It is a cyclic number.

It is not a de Polignac number, because 231021397 - 2³ = 231021389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231021317) 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, 202438 + ... + 203575.

It is an arithmetic number, because the mean of its divisors is an integer number (57856995).

Almost surely, 2^231021397 is an apocalyptic number.

It is an amenable number.

231021397 is a deficient number, since it is larger than the sum of its proper divisors (406583).

231021397 is an equidigital number, since it uses as much as digits as its factorization.

231021397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406582.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 231021397 is about 15199.3880468919. The cubic root of 231021397 is about 613.5981881938.

The spelling of 231021397 in words is "two hundred thirty-one million, twenty-one thousand, three hundred ninety-seven".