21257164 has 12 divisors (see below), whose sum is σ = 37356088. Its totient is φ = 10584000.

The previous prime is 21257141. The next prime is 21257177. The reversal of 21257164 is 46175212.

It is a plaindrome in base 16.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10062 + ... + 11989.

Almost surely, 2^21257164 is an apocalyptic number.

It is an amenable number.

21257164 is a deficient number, since it is larger than the sum of its proper divisors (16098924).

21257164 is a wasteful number, since it uses less digits than its factorization.

21257164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22296 (or 22294 counting only the distinct ones).

The product of its digits is 3360, while the sum is 28.

The square root of 21257164 is about 4610.5492080662. The cubic root of 21257164 is about 277.0140357027.

The spelling of 21257164 in words is "twenty-one million, two hundred fifty-seven thousand, one hundred sixty-four".