636345087721 has 16 divisors (see below), whose sum is σ = 759130988544. Its totient is φ = 521545291344.

The previous prime is 636345087691. The next prime is 636345087731. The reversal of 636345087721 is 127780543636.

It is not a de Polignac number, because 636345087721 - 2⁵ = 636345087689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636345087731) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 203925 + ... + 1146418.

It is an arithmetic number, because the mean of its divisors is an integer number (47445686784).

Almost surely, 2^636345087721 is an apocalyptic number.

It is an amenable number.

636345087721 is a deficient number, since it is larger than the sum of its proper divisors (122785900823).

636345087721 is a wasteful number, since it uses less digits than its factorization.

636345087721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1353300.

The product of its (nonzero) digits is 5080320, while the sum is 52.

The spelling of 636345087721 in words is "six hundred thirty-six billion, three hundred forty-five million, eighty-seven thousand, seven hundred twenty-one".