21631552 has 28 divisors (see below), whose sum is σ = 44313856. Its totient is φ = 10465920.

The previous prime is 21631541. The next prime is 21631573. The reversal of 21631552 is 25513612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3468 + ... + 7435.

Almost surely, 2^21631552 is an apocalyptic number.

It is an amenable number.

21631552 is an abundant number, since it is smaller than the sum of its proper divisors (22682304).

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

21631552 is a wasteful number, since it uses less digits than its factorization.

21631552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10946 (or 10936 counting only the distinct ones).

The product of its digits is 1800, while the sum is 25.

The square root of 21631552 is about 4650.9732314861. The cubic root of 21631552 is about 278.6308672015.

The spelling of 21631552 in words is "twenty-one million, six hundred thirty-one thousand, five hundred fifty-two".