636709663845 has 12 divisors (see below), whose sum is σ = 1103630084076. Its totient is φ = 339578487360.

The previous prime is 636709663819. The next prime is 636709663847. The reversal of 636709663845 is 548366907636.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 424121352516 + 212588311329 = 651246^2 + 461073^2 .

It is not a de Polignac number, because 636709663845 - 2¹⁸ = 636709401701 is a prime.

It is a super-2 number, since 2×636709663845² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636709663847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7074551776 + ... + 7074551865.

It is an arithmetic number, because the mean of its divisors is an integer number (91969173673).

Almost surely, 2^636709663845 is an apocalyptic number.

It is an amenable number.

636709663845 is a deficient number, since it is larger than the sum of its proper divisors (466920420231).

636709663845 is a wasteful number, since it uses less digits than its factorization.

636709663845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14149103652 (or 14149103649 counting only the distinct ones).

The product of its (nonzero) digits is 117573120, while the sum is 63.

The spelling of 636709663845 in words is "six hundred thirty-six billion, seven hundred nine million, six hundred sixty-three thousand, eight hundred forty-five".