21162560 has 56 divisors (see below), whose sum is σ = 51654456. Its totient is φ = 8253440.

The previous prime is 21162551. The next prime is 21162613. The reversal of 21162560 is 6526112.

It can be written as a sum of positive squares in 4 ways, for example, as 222784 + 20939776 = 472^2 + 4576^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

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, 12314 + ... + 13926.

It is an arithmetic number, because the mean of its divisors is an integer number (922401).

Almost surely, 2^21162560 is an apocalyptic number.

21162560 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 21162560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25827228).

21162560 is an abundant number, since it is smaller than the sum of its proper divisors (30491896).

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

21162560 is a wasteful number, since it uses less digits than its factorization.

21162560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1671 (or 1661 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21162560 is about 4600.2782524539. The cubic root of 21162560 is about 276.6024786174.

Adding to 21162560 its reverse (6526112), we get a palindrome (27688672).

The spelling of 21162560 in words is "twenty-one million, one hundred sixty-two thousand, five hundred sixty".