21164460 has 24 divisors (see below), whose sum is σ = 59260656. Its totient is φ = 5643840.

The previous prime is 21164459. The next prime is 21164477. The reversal of 21164460 is 6446112.

It is a self number, because there is not a number n which added to its sum of digits gives 21164460.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176311 + ... + 176430.

It is an arithmetic number, because the mean of its divisors is an integer number (2469194).

Almost surely, 2^21164460 is an apocalyptic number.

21164460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21164460 is an abundant number, since it is smaller than the sum of its proper divisors (38096196).

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

21164460 is a wasteful number, since it uses less digits than its factorization.

21164460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352753 (or 352751 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21164460 is about 4600.4847570664. The cubic root of 21164460 is about 276.6107562703.

The spelling of 21164460 in words is "twenty-one million, one hundred sixty-four thousand, four hundred sixty".