66221591547 has 4 divisors (see below), whose sum is σ = 88295455400. Its totient is φ = 44147727696.

The previous prime is 66221591539. The next prime is 66221591549. The reversal of 66221591547 is 74519512266.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66221591547 - 2³ = 66221591539 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66221591496 and 66221591505.

It is not an unprimeable number, because it can be changed into a prime (66221591549) 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, 11036931922 + ... + 11036931927.

It is an arithmetic number, because the mean of its divisors is an integer number (22073863850).

Almost surely, 2^66221591547 is an apocalyptic number.

66221591547 is a deficient number, since it is larger than the sum of its proper divisors (22073863853).

66221591547 is a wasteful number, since it uses less digits than its factorization.

66221591547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22073863852.

The product of its digits is 907200, while the sum is 48.

The spelling of 66221591547 in words is "sixty-six billion, two hundred twenty-one million, five hundred ninety-one thousand, five hundred forty-seven".