21400964 has 12 divisors (see below), whose sum is σ = 40332684. Its totient is φ = 9877344.

The previous prime is 21400949. The next prime is 21400979. The reversal of 21400964 is 46900412.

It is an interprime number because it is at equal distance from previous prime (21400949) and next prime (21400979).

It can be written as a sum of positive squares in 2 ways, for example, as 14002564 + 7398400 = 3742^2 + 2720^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 205727 + ... + 205830.

It is an arithmetic number, because the mean of its divisors is an integer number (3361057).

Almost surely, 2^21400964 is an apocalyptic number.

It is an amenable number.

21400964 is a deficient number, since it is larger than the sum of its proper divisors (18931720).

21400964 is a wasteful number, since it uses less digits than its factorization.

21400964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411574 (or 411572 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21400964 is about 4626.1175947008. The cubic root of 21400964 is about 277.6372786131.

The spelling of 21400964 in words is "twenty-one million, four hundred thousand, nine hundred sixty-four".