636661697 has 16 divisors (see below), whose sum is σ = 746380800. Its totient is φ = 531800640.

The previous prime is 636661693. The next prime is 636661699. The reversal of 636661697 is 796166636.

It is a happy number.

It is not a de Polignac number, because 636661697 - 2² = 636661693 is a prime.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636661693) 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 in 15 ways as a sum of consecutive naturals, for example, 39704 + ... + 53382.

It is an arithmetic number, because the mean of its divisors is an integer number (46648800).

Almost surely, 2^636661697 is an apocalyptic number.

It is an amenable number.

636661697 is a deficient number, since it is larger than the sum of its proper divisors (109719103).

636661697 is a wasteful number, since it uses less digits than its factorization.

636661697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13856.

The product of its digits is 1469664, while the sum is 50.

The square root of 636661697 is about 25232.1560117244. The cubic root of 636661697 is about 860.2728974397.

The spelling of 636661697 in words is "six hundred thirty-six million, six hundred sixty-one thousand, six hundred ninety-seven".