21660551306601 has 32 divisors (see below), whose sum is σ = 30492311224320. Its totient is φ = 13650070065984.

The previous prime is 21660551306587. The next prime is 21660551306627. The reversal of 21660551306601 is 10660315506612.

It is not a de Polignac number, because 21660551306601 - 2¹⁵ = 21660551273833 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21660551302601) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 879261 + ... + 6640346.

It is an arithmetic number, because the mean of its divisors is an integer number (952884725760).

Almost surely, 2^{21660551306601} is an apocalyptic number.

It is an amenable number.

21660551306601 is a deficient number, since it is larger than the sum of its proper divisors (8831759917719).

21660551306601 is a wasteful number, since it uses less digits than its factorization.

21660551306601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7520125.

The product of its (nonzero) digits is 194400, while the sum is 42.

The spelling of 21660551306601 in words is "twenty-one trillion, six hundred sixty billion, five hundred fifty-one million, three hundred six thousand, six hundred one".