21719538 has 48 divisors (see below), whose sum is σ = 48514752. Its totient is φ = 7020000.

The previous prime is 21719513. The next prime is 21719563. The reversal of 21719538 is 83591712.

It is an interprime number because it is at equal distance from previous prime (21719513) and next prime (21719563).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 143763 + ... + 143913.

It is an arithmetic number, because the mean of its divisors is an integer number (1010724).

Almost surely, 2^21719538 is an apocalyptic number.

21719538 is an abundant number, since it is smaller than the sum of its proper divisors (26795214).

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

21719538 is a wasteful number, since it uses less digits than its factorization.

21719538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351 (or 348 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 21719538 is about 4660.4225130346. The cubic root of 21719538 is about 279.0081317243.

The spelling of 21719538 in words is "twenty-one million, seven hundred nineteen thousand, five hundred thirty-eight".