21660535556140 has 48 divisors (see below), whose sum is σ = 49131493905312. Its totient is φ = 7974004018176.

The previous prime is 21660535556129. The next prime is 21660535556159. The reversal of 21660535556140 is 4165553506612.

It is a happy number.

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, 123517354 + ... + 123692593.

It is an arithmetic number, because the mean of its divisors is an integer number (1023572789694).

Almost surely, 2^{21660535556140} is an apocalyptic number.

21660535556140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21660535556140 is an abundant number, since it is smaller than the sum of its proper divisors (27470958349172).

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

21660535556140 is a wasteful number, since it uses less digits than its factorization.

21660535556140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247210306 (or 247210304 counting only the distinct ones).

The product of its (nonzero) digits is 3240000, while the sum is 49.

The spelling of 21660535556140 in words is "twenty-one trillion, six hundred sixty billion, five hundred thirty-five million, five hundred fifty-six thousand, one hundred forty".