21444868 has 6 divisors (see below), whose sum is σ = 37528526. Its totient is φ = 10722432.

The previous prime is 21444859. The next prime is 21444877. The reversal of 21444868 is 86844412.

It is an interprime number because it is at equal distance from previous prime (21444859) and next prime (21444877).

It can be written as a sum of positive squares in only one way, i.e., 19079424 + 2365444 = 4368^2 + 1538^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2680605 + ... + 2680612.

Almost surely, 2^21444868 is an apocalyptic number.

It is an amenable number.

21444868 is a deficient number, since it is larger than the sum of its proper divisors (16083658).

21444868 is a wasteful number, since it uses less digits than its factorization.

21444868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5361221 (or 5361219 counting only the distinct ones).

The product of its digits is 49152, while the sum is 37.

The square root of 21444868 is about 4630.8603952181. The cubic root of 21444868 is about 277.8270062203.

It can be divided in two parts, 21 and 444868, that added together give a square (444889 = 667²).

The spelling of 21444868 in words is "twenty-one million, four hundred forty-four thousand, eight hundred sixty-eight".