21698320 has 40 divisors (see below), whose sum is σ = 57657024. Its totient is φ = 7439232.

The previous prime is 21698311. The next prime is 21698321. The reversal of 21698320 is 2389612.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (21698321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18814 + ... + 19933.

Almost surely, 2^21698320 is an apocalyptic number.

21698320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21698320 is an abundant number, since it is smaller than the sum of its proper divisors (35958704).

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

21698320 is a wasteful number, since it uses less digits than its factorization.

21698320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38767 (or 38761 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 21698320 is about 4658.1455537585. The cubic root of 21698320 is about 278.9172469895.

The spelling of 21698320 in words is "twenty-one million, six hundred ninety-eight thousand, three hundred twenty".