21898164 has 12 divisors (see below), whose sum is σ = 51095744. Its totient is φ = 7299384.

The previous prime is 21898153. The next prime is 21898181. The reversal of 21898164 is 46189812.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 912412 + ... + 912435.

Almost surely, 2^21898164 is an apocalyptic number.

It is an amenable number.

21898164 is an abundant number, since it is smaller than the sum of its proper divisors (29197580).

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

21898164 is a wasteful number, since it uses less digits than its factorization.

21898164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1824854 (or 1824852 counting only the distinct ones).

The product of its digits is 27648, while the sum is 39.

The square root of 21898164 is about 4679.5474140135. The cubic root of 21898164 is about 279.7709180700.

The spelling of 21898164 in words is "twenty-one million, eight hundred ninety-eight thousand, one hundred sixty-four".