636079961 has 4 divisors (see below), whose sum is σ = 693905424. Its totient is φ = 578254500.

The previous prime is 636079919. The next prime is 636079991. The reversal of 636079961 is 169970636.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 636079961 - 2¹⁸ = 635817817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636079991) 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, 28912715 + ... + 28912736.

It is an arithmetic number, because the mean of its divisors is an integer number (173476356).

Almost surely, 2^636079961 is an apocalyptic number.

It is an amenable number.

636079961 is a deficient number, since it is larger than the sum of its proper divisors (57825463).

636079961 is a wasteful number, since it uses less digits than its factorization.

636079961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57825462.

The product of its (nonzero) digits is 367416, while the sum is 47.

The square root of 636079961 is about 25220.6257059574. The cubic root of 636079961 is about 860.0107989450.

The spelling of 636079961 in words is "six hundred thirty-six million, seventy-nine thousand, nine hundred sixty-one".