21385504 has 24 divisors (see below), whose sum is σ = 48117888. Its totient is φ = 9165120.

The previous prime is 21385471. The next prime is 21385513. The reversal of 21385504 is 40558312.

It is a Harshad number since it is a multiple of its sum of digits (28).

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, 47512 + ... + 47959.

It is an arithmetic number, because the mean of its divisors is an integer number (2004912).

Almost surely, 2^21385504 is an apocalyptic number.

It is an amenable number.

21385504 is an abundant number, since it is smaller than the sum of its proper divisors (26732384).

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

21385504 is an equidigital number, since it uses as much as digits as its factorization.

21385504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95488 (or 95480 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 21385504 is about 4624.4463452396. The cubic root of 21385504 is about 277.5704076952.

The spelling of 21385504 in words is "twenty-one million, three hundred eighty-five thousand, five hundred four".