21371538 has 16 divisors (see below), whose sum is σ = 43143840. Its totient is φ = 7057056.

The previous prime is 21371509. The next prime is 21371551. The reversal of 21371538 is 83517312.

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, 16003 + ... + 17286.

It is an arithmetic number, because the mean of its divisors is an integer number (2696490).

Almost surely, 2^21371538 is an apocalyptic number.

21371538 is an abundant number, since it is smaller than the sum of its proper divisors (21772302).

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

21371538 is a wasteful number, since it uses less digits than its factorization.

21371538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33401.

The product of its digits is 5040, while the sum is 30.

The square root of 21371538 is about 4622.9360800253. The cubic root of 21371538 is about 277.5099712349.

The spelling of 21371538 in words is "twenty-one million, three hundred seventy-one thousand, five hundred thirty-eight".