21666364322660 has 96 divisors (see below), whose sum is σ = 48901554430848. Its totient is φ = 8033903032320.

The previous prime is 21666364322653. The next prime is 21666364322749. The reversal of 21666364322660 is 6622346366612.

It is a happy number.

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, 176278547 + ... + 176401413.

It is an arithmetic number, because the mean of its divisors is an integer number (509391191988).

Almost surely, 2^{21666364322660} is an apocalyptic number.

21666364322660 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 21666364322660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24450777215424).

21666364322660 is an abundant number, since it is smaller than the sum of its proper divisors (27235190108188).

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

21666364322660 is a wasteful number, since it uses less digits than its factorization.

21666364322660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130701 (or 130699 counting only the distinct ones).

The product of its (nonzero) digits is 13436928, while the sum is 53.

The spelling of 21666364322660 in words is "twenty-one trillion, six hundred sixty-six billion, three hundred sixty-four million, three hundred twenty-two thousand, six hundred sixty".