21057164 has 6 divisors (see below), whose sum is σ = 36850044. Its totient is φ = 10528580.

The previous prime is 21057151. The next prime is 21057173. The reversal of 21057164 is 46175012.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2632142 + ... + 2632149.

It is an arithmetic number, because the mean of its divisors is an integer number (6141674).

Almost surely, 2^21057164 is an apocalyptic number.

It is an amenable number.

21057164 is a deficient number, since it is larger than the sum of its proper divisors (15792880).

21057164 is a wasteful number, since it uses less digits than its factorization.

21057164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5264295 (or 5264293 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21057164 is about 4588.8085599641. The cubic root of 21057164 is about 276.1425259811.

The spelling of 21057164 in words is "twenty-one million, fifty-seven thousand, one hundred sixty-four".