636987553225 has 9 divisors (see below), whose sum is σ = 789869514343. Its totient is φ = 509586850120.

The previous prime is 636987553177. The next prime is 636987553249. The reversal of 636987553225 is 522355789636.

It is a happy number.

The square root of 636987553225 is 798115.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 229315519161 + 407672034064 = 478869^2 + 638492^2 .

It is not a de Polignac number, because 636987553225 - 2¹¹ = 636987551177 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3910764 + ... + 4070386.

Almost surely, 2^636987553225 is an apocalyptic number.

636987553225 is the 798115-th square number.

636987553225 is the 399058-th centered octagonal number.

It is an amenable number.

636987553225 is a deficient number, since it is larger than the sum of its proper divisors (152881961118).

636987553225 is an frugal number, since it uses more digits than its factorization.

636987553225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319256 (or 159628 counting only the distinct ones).

The product of its digits is 81648000, while the sum is 61.

The spelling of 636987553225 in words is "six hundred thirty-six billion, nine hundred eighty-seven million, five hundred fifty-three thousand, two hundred twenty-five".