21801360 has 160 divisors (see below), whose sum is σ = 81423360. Its totient is φ = 4713984.

The previous prime is 21801347. The next prime is 21801371. The reversal of 21801360 is 6310812.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31579 + ... + 32261.

It is an arithmetic number, because the mean of its divisors is an integer number (508896).

Almost surely, 2^21801360 is an apocalyptic number.

21801360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21801360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40711680).

21801360 is an abundant number, since it is smaller than the sum of its proper divisors (59622000).

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

21801360 is a wasteful number, since it uses less digits than its factorization.

21801360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 725 (or 719 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21801360 is about 4669.1926496987. The cubic root of 21801360 is about 279.3580531638.

The spelling of 21801360 in words is "twenty-one million, eight hundred one thousand, three hundred sixty".