21719898 has 24 divisors (see below), whose sum is σ = 48683700. Its totient is φ = 6990144.

The previous prime is 21719881. The next prime is 21719911. The reversal of 21719898 is 89891712.

It can be written as a sum of positive squares in 2 ways, for example, as 19740249 + 1979649 = 4443^2 + 1407^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20283 + ... + 21326.

Almost surely, 2^21719898 is an apocalyptic number.

21719898 is an abundant number, since it is smaller than the sum of its proper divisors (26963802).

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

21719898 is a wasteful number, since it uses less digits than its factorization.

21719898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41646 (or 41643 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 21719898 is about 4660.4611359821. The cubic root of 21719898 is about 279.0096732300.

The spelling of 21719898 in words is "twenty-one million, seven hundred nineteen thousand, eight hundred ninety-eight".