231396021 has 12 divisors (see below), whose sum is σ = 346618272. Its totient is φ = 154263852.

The previous prime is 231396019. The next prime is 231396023. The reversal of 231396021 is 120693132.

231396021 is a `hidden beast` number, since 23 + 1 + 39 + 602 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (231396019) and next prime (231396023).

It is not a de Polignac number, because 231396021 - 2¹ = 231396019 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231396023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 475881 + ... + 476366.

It is an arithmetic number, because the mean of its divisors is an integer number (28884856).

Almost surely, 2^231396021 is an apocalyptic number.

It is an amenable number.

231396021 is a deficient number, since it is larger than the sum of its proper divisors (115222251).

231396021 is an frugal number, since it uses more digits than its factorization.

231396021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 952262 (or 952250 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 231396021 is about 15211.7067089791. The cubic root of 231396021 is about 613.9296790873.

The spelling of 231396021 in words is "two hundred thirty-one million, three hundred ninety-six thousand, twenty-one".