21231164 has 48 divisors (see below), whose sum is σ = 41313888. Its totient is φ = 9504768.

The previous prime is 21231143. The next prime is 21231173. The reversal of 21231164 is 46113212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154904 + ... + 155040.

It is an arithmetic number, because the mean of its divisors is an integer number (860706).

Almost surely, 2^21231164 is an apocalyptic number.

It is an amenable number.

21231164 is a deficient number, since it is larger than the sum of its proper divisors (20082724).

21231164 is a wasteful number, since it uses less digits than its factorization.

21231164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 252 counting only the distinct ones).

The product of its digits is 288, while the sum is 20.

The square root of 21231164 is about 4607.7287246538. The cubic root of 21231164 is about 276.9010494271.

Adding to 21231164 its reverse (46113212), we get a palindrome (67344376).

The spelling of 21231164 in words is "twenty-one million, two hundred thirty-one thousand, one hundred sixty-four".