21552660 has 36 divisors (see below), whose sum is σ = 65376948. Its totient is φ = 5747328.

The previous prime is 21552659. The next prime is 21552667. The reversal of 21552660 is 6625512.

It can be written as a sum of positive squares in 2 ways, for example, as 8678916 + 12873744 = 2946^2 + 3588^2 .

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 (21552667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59689 + ... + 60048.

Almost surely, 2^21552660 is an apocalyptic number.

21552660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21552660 is an abundant number, since it is smaller than the sum of its proper divisors (43824288).

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

21552660 is a wasteful number, since it uses less digits than its factorization.

21552660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119752 (or 119747 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 21552660 is about 4642.4842487616. The cubic root of 21552660 is about 278.2917248888.

The spelling of 21552660 in words is "twenty-one million, five hundred fifty-two thousand, six hundred sixty".