635661945 has 16 divisors (see below), whose sum is σ = 1130065920. Its totient is φ = 339019632.

The previous prime is 635661937. The next prime is 635661947. The reversal of 635661945 is 549166536.

635661945 is a `hidden beast` number, since 635 + 6 + 6 + 1 + 9 + 4 + 5 = 666.

It is not a de Polignac number, because 635661945 - 2³ = 635661937 is a prime.

It is a super-2 number, since 2×635661945² = 808132216642366050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 635661945.

It is not an unprimeable number, because it can be changed into a prime (635661947) 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, 2354169 + ... + 2354438.

It is an arithmetic number, because the mean of its divisors is an integer number (70629120).

Almost surely, 2^635661945 is an apocalyptic number.

It is an amenable number.

635661945 is a deficient number, since it is larger than the sum of its proper divisors (494403975).

635661945 is a wasteful number, since it uses less digits than its factorization.

635661945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4708621 (or 4708615 counting only the distinct ones).

The product of its digits is 583200, while the sum is 45.

The square root of 635661945 is about 25212.3371586214. The cubic root of 635661945 is about 859.8223650603.

The spelling of 635661945 in words is "six hundred thirty-five million, six hundred sixty-one thousand, nine hundred forty-five".