21633552 has 60 divisors (see below), whose sum is σ = 63738480. Its totient is φ = 6830784.

The previous prime is 21633551. The next prime is 21633553. The reversal of 21633552 is 25533612.

21633552 is a `hidden beast` number, since 21 + 633 + 5 + 5 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (21633551) and next prime (21633553).

It is not an unprimeable number, because it can be changed into a prime (21633551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1218 + ... + 6689.

It is an arithmetic number, because the mean of its divisors is an integer number (1062308).

Almost surely, 2^21633552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21633552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31869240).

21633552 is an abundant number, since it is smaller than the sum of its proper divisors (42104928).

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

21633552 is a wasteful number, since it uses less digits than its factorization.

21633552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7940 (or 7931 counting only the distinct ones).

The product of its digits is 5400, while the sum is 27.

The square root of 21633552 is about 4651.1882352792. The cubic root of 21633552 is about 278.6394541114.

The spelling of 21633552 in words is "twenty-one million, six hundred thirty-three thousand, five hundred fifty-two".