21660614026521 has 16 divisors (see below), whose sum is σ = 28926538872000. Its totient is φ = 14417559871488.

The previous prime is 21660614026453. The next prime is 21660614026531. The reversal of 21660614026521 is 12562041606612.

It is not a de Polignac number, because 21660614026521 - 2³¹ = 21658466542873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21660614026531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6859405 + ... + 9506453.

It is an arithmetic number, because the mean of its divisors is an integer number (1807908679500).

Almost surely, 2^{21660614026521} is an apocalyptic number.

It is an amenable number.

21660614026521 is a deficient number, since it is larger than the sum of its proper divisors (7265924845479).

21660614026521 is a wasteful number, since it uses less digits than its factorization.

21660614026521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2651368.

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 21660614026521 in words is "twenty-one trillion, six hundred sixty billion, six hundred fourteen million, twenty-six thousand, five hundred twenty-one".