21140538 has 16 divisors (see below), whose sum is σ = 42378336. Its totient is φ = 7030640.

The previous prime is 21140513. The next prime is 21140549. The reversal of 21140538 is 83504112.

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, 1056 + ... + 6587.

It is an arithmetic number, because the mean of its divisors is an integer number (2648646).

Almost surely, 2^21140538 is an apocalyptic number.

21140538 is an abundant number, since it is smaller than the sum of its proper divisors (21237798).

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

21140538 is a wasteful number, since it uses less digits than its factorization.

21140538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8109.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 21140538 is about 4597.8840785735. The cubic root of 21140538 is about 276.5065000919.

The spelling of 21140538 in words is "twenty-one million, one hundred forty thousand, five hundred thirty-eight".