21486724 has 24 divisors (see below), whose sum is σ = 43360128. Its totient is φ = 9125760.

The previous prime is 21486697. The next prime is 21486733. The reversal of 21486724 is 42768412.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21486724.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 232 + ... + 6559.

It is an arithmetic number, because the mean of its divisors is an integer number (1806672).

Almost surely, 2^21486724 is an apocalyptic number.

It is an amenable number.

21486724 is an abundant number, since it is smaller than the sum of its proper divisors (21873404).

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

21486724 is a wasteful number, since it uses less digits than its factorization.

21486724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6915 (or 6913 counting only the distinct ones).

The product of its digits is 21504, while the sum is 34.

The square root of 21486724 is about 4635.3774387853. The cubic root of 21486724 is about 278.0076425965.

The spelling of 21486724 in words is "twenty-one million, four hundred eighty-six thousand, seven hundred twenty-four".