21621166661201 has 8 divisors (see below), whose sum is σ = 22318678867200. Its totient is φ = 20923657906320.

The previous prime is 21621166661179. The next prime is 21621166661207. The reversal of 21621166661201 is 10216666112612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21621166661201 - 2¹⁴ = 21621166644817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621166661207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19492190 + ... + 20571528.

It is an arithmetic number, because the mean of its divisors is an integer number (2789834858400).

Almost surely, 2^{21621166661201} is an apocalyptic number.

It is an amenable number.

21621166661201 is a deficient number, since it is larger than the sum of its proper divisors (697512205999).

21621166661201 is a wasteful number, since it uses less digits than its factorization.

21621166661201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1725559.

The product of its (nonzero) digits is 62208, while the sum is 41.

The spelling of 21621166661201 in words is "twenty-one trillion, six hundred twenty-one billion, one hundred sixty-six million, six hundred sixty-one thousand, two hundred one".