21643632 has 40 divisors (see below), whose sum is σ = 62126480. Its totient is φ = 7214400.

The previous prime is 21643607. The next prime is 21643691. The reversal of 21643632 is 23634612.

21643632 is a `hidden beast` number, since 21 + 6 + 4 + 3 + 632 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

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

It is a junction number, because it is equal to n+sod(n) for n = 21643596 and 21643605.

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, 24619 + ... + 25482.

It is an arithmetic number, because the mean of its divisors is an integer number (1553162).

Almost surely, 2^21643632 is an apocalyptic number.

It is an amenable number.

21643632 is an abundant number, since it is smaller than the sum of its proper divisors (40482848).

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

21643632 is a wasteful number, since it uses less digits than its factorization.

21643632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50118 (or 50106 counting only the distinct ones).

The product of its digits is 5184, while the sum is 27.

The square root of 21643632 is about 4652.2717031575. The cubic root of 21643632 is about 278.6827240836.

The spelling of 21643632 in words is "twenty-one million, six hundred forty-three thousand, six hundred thirty-two".