21629664 has 72 divisors (see below), whose sum is σ = 70302960. Its totient is φ = 6179328.

The previous prime is 21629617. The next prime is 21629687. The reversal of 21629664 is 46692612.

21629664 is a `hidden beast` number, since 21 + 629 + 6 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3349 + ... + 7380.

It is an arithmetic number, because the mean of its divisors is an integer number (976430).

Almost surely, 2^21629664 is an apocalyptic number.

21629664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21629664 is an abundant number, since it is smaller than the sum of its proper divisors (48673296).

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

21629664 is a wasteful number, since it uses less digits than its factorization.

21629664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10752 (or 10741 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21629664 is about 4650.7702587851. The cubic root of 21629664 is about 278.6227606729.

The spelling of 21629664 in words is "twenty-one million, six hundred twenty-nine thousand, six hundred sixty-four".