66221567 has 2 divisors, whose sum is σ = 66221568. Its totient is φ = 66221566.

The previous prime is 66221537. The next prime is 66221569. The reversal of 66221567 is 76512266.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66221567 - 2¹² = 66217471 is a prime.

Together with 66221569, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66221569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33110783 + 33110784.

It is an arithmetic number, because the mean of its divisors is an integer number (33110784).

Almost surely, 2^66221567 is an apocalyptic number.

66221567 is a deficient number, since it is larger than the sum of its proper divisors (1).

66221567 is an equidigital number, since it uses as much as digits as its factorization.

66221567 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 35.

The square root of 66221567 is about 8137.6634853009. The cubic root of 66221567 is about 404.5757219162.

The spelling of 66221567 in words is "sixty-six million, two hundred twenty-one thousand, five hundred sixty-seven".