635781681168 has 20 divisors (see below), whose sum is σ = 1642436009808. Its totient is φ = 211927227040.

The previous prime is 635781681103. The next prime is 635781681169. The reversal of 635781681168 is 861186187536.

It is a happy number.

It is a super-2 number, since 2×635781681168² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (635781681169) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6622725798 + ... + 6622725893.

Almost surely, 2^635781681168 is an apocalyptic number.

It is an amenable number.

635781681168 is an abundant number, since it is smaller than the sum of its proper divisors (1006654328640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

635781681168 is a wasteful number, since it uses less digits than its factorization.

635781681168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13245451702 (or 13245451696 counting only the distinct ones).

The product of its digits is 11612160, while the sum is 60.

The spelling of 635781681168 in words is "six hundred thirty-five billion, seven hundred eighty-one million, six hundred eighty-one thousand, one hundred sixty-eight".