21238520 has 32 divisors (see below), whose sum is σ = 48021120. Its totient is φ = 8453760.

The previous prime is 21238519. The next prime is 21238543. The reversal of 21238520 is 2583212.

It is a congruent number.

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, 7730 + ... + 10110.

It is an arithmetic number, because the mean of its divisors is an integer number (1500660).

Almost surely, 2^21238520 is an apocalyptic number.

21238520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21238520 is an abundant number, since it is smaller than the sum of its proper divisors (26782600).

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

21238520 is a wasteful number, since it uses less digits than its factorization.

21238520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2615 (or 2611 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21238520 is about 4608.5268796005. The cubic root of 21238520 is about 276.9330252045.

The spelling of 21238520 in words is "twenty-one million, two hundred thirty-eight thousand, five hundred twenty".