21808160 has 48 divisors (see below), whose sum is σ = 56210112. Its totient is φ = 7929600.

The previous prime is 21808153. The next prime is 21808177. The reversal of 21808160 is 6180812.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4436 + ... + 7955.

It is an arithmetic number, because the mean of its divisors is an integer number (1171044).

Almost surely, 2^21808160 is an apocalyptic number.

21808160 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21808160 is an abundant number, since it is smaller than the sum of its proper divisors (34401952).

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

21808160 is a wasteful number, since it uses less digits than its factorization.

21808160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12417 (or 12409 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 21808160 is about 4669.9207702059. The cubic root of 21808160 is about 279.3870947357.

Adding to 21808160 its reverse (6180812), we get a palindrome (27988972).

The spelling of 21808160 in words is "twenty-one million, eight hundred eight thousand, one hundred sixty".