66221497 has 2 divisors, whose sum is σ = 66221498. Its totient is φ = 66221496.

The previous prime is 66221399. The next prime is 66221537. The reversal of 66221497 is 79412266.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52113961 + 14107536 = 7219^2 + 3756^2 .

It is a cyclic number.

It is not a de Polignac number, because 66221497 - 2⁷ = 66221369 is a prime.

It is not a weakly prime, because it can be changed into another prime (66921497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33110748 + 33110749.

It is an arithmetic number, because the mean of its divisors is an integer number (33110749).

Almost surely, 2^66221497 is an apocalyptic number.

It is an amenable number.

66221497 is a deficient number, since it is larger than the sum of its proper divisors (1).

66221497 is an equidigital number, since it uses as much as digits as its factorization.

66221497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 37.

The square root of 66221497 is about 8137.6591843109. The cubic root of 66221497 is about 404.5755793629.

The spelling of 66221497 in words is "sixty-six million, two hundred twenty-one thousand, four hundred ninety-seven".