21438568 has 24 divisors (see below), whose sum is σ = 40792050. Its totient is φ = 10562912.

The previous prime is 21438541. The next prime is 21438589. The reversal of 21438568 is 86583412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20088324 + 1350244 = 4482^2 + 1162^2 .

It is a super-2 number, since 2×21438568² = 919224395781248, which contains 22 as substring.

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, 54918 + ... + 55306.

Almost surely, 2^21438568 is an apocalyptic number.

It is an amenable number.

21438568 is a deficient number, since it is larger than the sum of its proper divisors (19353482).

21438568 is an equidigital number, since it uses as much as digits as its factorization.

21438568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561 (or 474 counting only the distinct ones).

The product of its digits is 46080, while the sum is 37.

The square root of 21438568 is about 4630.1801260858. The cubic root of 21438568 is about 277.7997971997.

The spelling of 21438568 in words is "twenty-one million, four hundred thirty-eight thousand, five hundred sixty-eight".