21608568 has 24 divisors (see below), whose sum is σ = 58523400. Its totient is φ = 7202832.

The previous prime is 21608551. The next prime is 21608603. The reversal of 21608568 is 86580612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×21608568² = 933860422021248, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 149988 + ... + 150131.

It is an arithmetic number, because the mean of its divisors is an integer number (2438475).

Almost surely, 2^21608568 is an apocalyptic number.

It is an amenable number.

21608568 is an abundant number, since it is smaller than the sum of its proper divisors (36914832).

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

21608568 is a wasteful number, since it uses less digits than its factorization.

21608568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300131 (or 300124 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 21608568 is about 4648.5016940946. The cubic root of 21608568 is about 278.5321484204.

It can be divided in two parts, 216085 and 68, that added together give a triangular number (216153 = T₆₅₇).

The spelling of 21608568 in words is "twenty-one million, six hundred eight thousand, five hundred sixty-eight".