231221538 has 12 divisors (see below), whose sum is σ = 500980038. Its totient is φ = 77073840.

The previous prime is 231221521. The next prime is 231221561. The reversal of 231221538 is 835122132.

231221538 is a `hidden beast` number, since 2 + 3 + 122 + 1 + 538 = 666.

It can be written as a sum of positive squares in only one way, i.e., 126630009 + 104591529 = 11253^2 + 10227^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6422803 + ... + 6422838.

Almost surely, 2^231221538 is an apocalyptic number.

231221538 is an abundant number, since it is smaller than the sum of its proper divisors (269758500).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231221538 is a wasteful number, since it uses less digits than its factorization.

231221538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12845649 (or 12845646 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 231221538 is about 15205.9704721534. The cubic root of 231221538 is about 613.7753300950.

The spelling of 231221538 in words is "two hundred thirty-one million, two hundred twenty-one thousand, five hundred thirty-eight".