66264659921 has 2 divisors, whose sum is σ = 66264659922. Its totient is φ = 66264659920.

The previous prime is 66264659893. The next prime is 66264660013. The reversal of 66264659921 is 12995646266.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45460636225 + 20804023696 = 213215^2 + 144236^2 .

It is a cyclic number.

It is not a de Polignac number, because 66264659921 - 2³⁴ = 49084790737 is a prime.

It is not a weakly prime, because it can be changed into another prime (66264655921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33132329960 + 33132329961.

It is an arithmetic number, because the mean of its divisors is an integer number (33132329961).

Almost surely, 2^66264659921 is an apocalyptic number.

It is an amenable number.

66264659921 is a deficient number, since it is larger than the sum of its proper divisors (1).

66264659921 is an equidigital number, since it uses as much as digits as its factorization.

66264659921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8398080, while the sum is 56.

The spelling of 66264659921 in words is "sixty-six billion, two hundred sixty-four million, six hundred fifty-nine thousand, nine hundred twenty-one".