21164964 has 12 divisors (see below), whose sum is σ = 49384944. Its totient is φ = 7054984.

The previous prime is 21164953. The next prime is 21164989. The reversal of 21164964 is 46946112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21164964² = 895911402242592, which contains 22 as substring.

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, 881862 + ... + 881885.

It is an arithmetic number, because the mean of its divisors is an integer number (4115412).

Almost surely, 2^21164964 is an apocalyptic number.

It is an amenable number.

21164964 is an abundant number, since it is smaller than the sum of its proper divisors (28219980).

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

21164964 is a wasteful number, since it uses less digits than its factorization.

21164964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1763754 (or 1763752 counting only the distinct ones).

The product of its digits is 10368, while the sum is 33.

The square root of 21164964 is about 4600.5395335765. The cubic root of 21164964 is about 276.6129519436.

The spelling of 21164964 in words is "twenty-one million, one hundred sixty-four thousand, nine hundred sixty-four".