21170560 has 64 divisors (see below), whose sum is σ = 53305200. Its totient is φ = 8017920.

The previous prime is 21170543. The next prime is 21170563. The reversal of 21170560 is 6507112.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×21170560² = 896385221427200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21170563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11290 + ... + 13030.

Almost surely, 2^21170560 is an apocalyptic number.

21170560 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 21170560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26652600).

21170560 is an abundant number, since it is smaller than the sum of its proper divisors (32134640).

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

21170560 is a wasteful number, since it uses less digits than its factorization.

21170560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1779 (or 1767 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 21170560 is about 4601.1476829156. The cubic root of 21170560 is about 276.6373285450.

Adding to 21170560 its reverse (6507112), we get a palindrome (27677672).

The spelling of 21170560 in words is "twenty-one million, one hundred seventy thousand, five hundred sixty".