21408696 has 48 divisors (see below), whose sum is σ = 58203600. Its totient is φ = 7108992.

The previous prime is 21408679. The next prime is 21408697. The reversal of 21408696 is 69680412.

21408696 is a nontrivial binomial coefficient, being equal to C(6544, 2).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21408696.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21408697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29085 + ... + 29811.

It is an arithmetic number, because the mean of its divisors is an integer number (1212575).

Almost surely, 2^21408696 is an apocalyptic number.

21408696 is the 6543-rd triangular number and also the 3272-nd hexagonal number.

It is an amenable number.

21408696 is an abundant number, since it is smaller than the sum of its proper divisors (36794904).

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

21408696 is a wasteful number, since it uses less digits than its factorization.

21408696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148 (or 1141 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 21408696 is about 4626.9532091864. The cubic root of 21408696 is about 277.6707106423.

The spelling of 21408696 in words is "twenty-one million, four hundred eight thousand, six hundred ninety-six".