21666224641635 has 40 divisors (see below), whose sum is σ = 44387101493856. Its totient is φ = 9904559834880.

The previous prime is 21666224641601. The next prime is 21666224641639. The reversal of 21666224641635 is 53614642266612.

It is not a de Polignac number, because 21666224641635 - 2⁷ = 21666224641507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21666224641639) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3821200806 + ... + 3821206475.

Almost surely, 2^{21666224641635} is an apocalyptic number.

21666224641635 is an abundant number, since it is smaller than the sum of its proper divisors (22720876852221).

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

21666224641635 is an equidigital number, since it uses as much as digits as its factorization.

21666224641635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7642407305 (or 7642407296 counting only the distinct ones).

The product of its digits is 14929920, while the sum is 54.

The spelling of 21666224641635 in words is "twenty-one trillion, six hundred sixty-six billion, two hundred twenty-four million, six hundred forty-one thousand, six hundred thirty-five".