21164764 has 24 divisors (see below), whose sum is σ = 37912448. Its totient is φ = 10335600.

The previous prime is 21164713. The next prime is 21164771. The reversal of 21164764 is 46746112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40207 + ... + 40729.

Almost surely, 2^21164764 is an apocalyptic number.

It is an amenable number.

21164764 is a deficient number, since it is larger than the sum of its proper divisors (16747684).

21164764 is a wasteful number, since it uses less digits than its factorization.

21164764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 745 (or 743 counting only the distinct ones).

The product of its digits is 8064, while the sum is 31.

The square root of 21164764 is about 4600.5177969442. The cubic root of 21164764 is about 276.6120806488.

The spelling of 21164764 in words is "twenty-one million, one hundred sixty-four thousand, seven hundred sixty-four".