66221867799 has 12 divisors (see below), whose sum is σ = 96206723496. Its totient is φ = 43892720592.

The previous prime is 66221867783. The next prime is 66221867809. The reversal of 66221867799 is 99776812266.

66221867799 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66221867799 - 2⁴ = 66221867783 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66221862799) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21264297 + ... + 21267410.

It is an arithmetic number, because the mean of its divisors is an integer number (8017226958).

Almost surely, 2^66221867799 is an apocalyptic number.

66221867799 is a deficient number, since it is larger than the sum of its proper divisors (29984855697).

66221867799 is a wasteful number, since it uses less digits than its factorization.

66221867799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42531886 (or 42531883 counting only the distinct ones).

The product of its digits is 27433728, while the sum is 63.

The spelling of 66221867799 in words is "sixty-six billion, two hundred twenty-one million, eight hundred sixty-seven thousand, seven hundred ninety-nine".