636731161 has 12 divisors (see below), whose sum is σ = 703567872. Its totient is φ = 575795000.

The previous prime is 636731111. The next prime is 636731167. The reversal of 636731161 is 161137636.

It is not a de Polignac number, because 636731161 - 2⁷ = 636731033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636731167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9336 + ... + 36886.

It is an arithmetic number, because the mean of its divisors is an integer number (58630656).

Almost surely, 2^636731161 is an apocalyptic number.

It is an amenable number.

636731161 is a deficient number, since it is larger than the sum of its proper divisors (66836711).

636731161 is a wasteful number, since it uses less digits than its factorization.

636731161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27764 (or 27753 counting only the distinct ones).

The product of its digits is 13608, while the sum is 34.

The square root of 636731161 is about 25233.5324716933. The cubic root of 636731161 is about 860.3041834553.

Adding to 636731161 its reverse (161137636), we get a palindrome (797868797).

The spelling of 636731161 in words is "six hundred thirty-six million, seven hundred thirty-one thousand, one hundred sixty-one".