21869568 has 176 divisors, whose sum is σ = 74674560. Its totient is φ = 6193152.

The previous prime is 21869563. The next prime is 21869569. The reversal of 21869568 is 86596812.

21869568 is a `hidden beast` number, since 2 + 1 + 86 + 9 + 568 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21869563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 193480 + ... + 193592.

Almost surely, 2^21869568 is an apocalyptic number.

21869568 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21869568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37337280).

21869568 is an abundant number, since it is smaller than the sum of its proper divisors (52804992).

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

21869568 is a wasteful number, since it uses less digits than its factorization.

21869568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 125 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 21869568 is about 4676.4909921863. The cubic root of 21869568 is about 279.6490842008.

The spelling of 21869568 in words is "twenty-one million, eight hundred sixty-nine thousand, five hundred sixty-eight".