21400868 has 6 divisors (see below), whose sum is σ = 37451526. Its totient is φ = 10700432.

The previous prime is 21400849. The next prime is 21400877. The reversal of 21400868 is 86800412.

It can be written as a sum of positive squares in only one way, i.e., 18992164 + 2408704 = 4358^2 + 1552^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21400868.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2675105 + ... + 2675112.

It is an arithmetic number, because the mean of its divisors is an integer number (6241921).

Almost surely, 2^21400868 is an apocalyptic number.

It is an amenable number.

21400868 is a deficient number, since it is larger than the sum of its proper divisors (16050658).

21400868 is a wasteful number, since it uses less digits than its factorization.

21400868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5350221 (or 5350219 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 21400868 is about 4626.1072188180. The cubic root of 21400868 is about 277.6368634726.

The spelling of 21400868 in words is "twenty-one million, four hundred thousand, eight hundred sixty-eight".