21624768 has 84 divisors (see below), whose sum is σ = 67638168. Its totient is φ = 6551040.

The previous prime is 21624767. The next prime is 21624769. The reversal of 21624768 is 86742612.

21624768 is a `hidden beast` number, since 21 + 624 + 7 + 6 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (21624767) and next prime (21624769).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21624767) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 4630 + ... + 8042.

Almost surely, 2^21624768 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 21624768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33819084).

21624768 is an abundant number, since it is smaller than the sum of its proper divisors (46013400).

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

21624768 is a wasteful number, since it uses less digits than its factorization.

21624768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3442 (or 3429 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 21624768 is about 4650.2438645731. The cubic root of 21624768 is about 278.6017364601.

The spelling of 21624768 in words is "twenty-one million, six hundred twenty-four thousand, seven hundred sixty-eight".