21601666754660 has 48 divisors (see below), whose sum is σ = 46068581079360. Its totient is φ = 8507321462400.

The previous prime is 21601666754557. The next prime is 21601666754693. The reversal of 21601666754660 is 6645766610612.

It is a junction number, because it is equal to n+sod(n) for n = 21601666754596 and 21601666754605.

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, 29509634 + ... + 30232793.

It is an arithmetic number, because the mean of its divisors is an integer number (959762105820).

Almost surely, 2^{21601666754660} is an apocalyptic number.

21601666754660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21601666754660 is an abundant number, since it is smaller than the sum of its proper divisors (24466914324700).

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

21601666754660 is a wasteful number, since it uses less digits than its factorization.

21601666754660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59742716 (or 59742714 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 56.

The spelling of 21601666754660 in words is "twenty-one trillion, six hundred one billion, six hundred sixty-six million, seven hundred fifty-four thousand, six hundred sixty".