21660354110640 has 80 divisors (see below), whose sum is σ = 76739540283648. Its totient is φ = 4950938082048.

The previous prime is 21660354110623. The next prime is 21660354110669. The reversal of 21660354110640 is 4601145306612.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21660354110640² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6446532282 + ... + 6446535641.

Almost surely, 2^{21660354110640} is an apocalyptic number.

21660354110640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21660354110640 is an abundant number, since it is smaller than the sum of its proper divisors (55079186173008).

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

21660354110640 is a wasteful number, since it uses less digits than its factorization.

21660354110640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12893067946 (or 12893067940 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 39.

The spelling of 21660354110640 in words is "twenty-one trillion, six hundred sixty billion, three hundred fifty-four million, one hundred ten thousand, six hundred forty".