21660551236001 has 4 divisors (see below), whose sum is σ = 21660726750000. Its totient is φ = 21660375722004.

The previous prime is 21660551235979. The next prime is 21660551236003. The reversal of 21660551236001 is 10063215506612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21660551236001 - 2²⁶ = 21660484127137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21660551236003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87571751 + ... + 87818748.

It is an arithmetic number, because the mean of its divisors is an integer number (5415181687500).

Almost surely, 2^{21660551236001} is an apocalyptic number.

It is an amenable number.

21660551236001 is a deficient number, since it is larger than the sum of its proper divisors (175513999).

21660551236001 is a wasteful number, since it uses less digits than its factorization.

21660551236001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175513998.

The product of its (nonzero) digits is 64800, while the sum is 38.

The spelling of 21660551236001 in words is "twenty-one trillion, six hundred sixty billion, five hundred fifty-one million, two hundred thirty-six thousand, one".