21998160 has 60 divisors (see below), whose sum is σ = 73879572. Its totient is φ = 5865984.

The previous prime is 21998159. The next prime is 21998173. The reversal of 21998160 is 6189912.

It can be written as a sum of positive squares in 2 ways, for example, as 5934096 + 16064064 = 2436^2 + 4008^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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, 14557 + ... + 15996.

Almost surely, 2^21998160 is an apocalyptic number.

21998160 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21998160 is an abundant number, since it is smaller than the sum of its proper divisors (51881412).

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

21998160 is a wasteful number, since it uses less digits than its factorization.

21998160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30572 (or 30563 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 21998160 is about 4690.2196110630. The cubic root of 21998160 is about 280.1961211017.

The spelling of 21998160 in words is "twenty-one million, nine hundred ninety-eight thousand, one hundred sixty".