21732660 has 36 divisors (see below), whose sum is σ = 65922948. Its totient is φ = 5795328.

The previous prime is 21732593. The next prime is 21732661. The reversal of 21732660 is 6623712.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14699556 + 7033104 = 3834^2 + 2652^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21732661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60189 + ... + 60548.

It is an arithmetic number, because the mean of its divisors is an integer number (1831193).

Almost surely, 2^21732660 is an apocalyptic number.

21732660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21732660 is an abundant number, since it is smaller than the sum of its proper divisors (44190288).

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

21732660 is a wasteful number, since it uses less digits than its factorization.

21732660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120752 (or 120747 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 21732660 is about 4661.8301127347. The cubic root of 21732660 is about 279.0643086045.

The spelling of 21732660 in words is "twenty-one million, seven hundred thirty-two thousand, six hundred sixty".