661535756616 has 64 divisors (see below), whose sum is σ = 1890164465280. Its totient is φ = 189003985920.

The previous prime is 661535756611. The next prime is 661535756617. The reversal of 661535756616 is 616657535166.

It is a hoax number, since the sum of its digits (57) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (661535756611) 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, 8080560 + ... + 8162016.

It is an arithmetic number, because the mean of its divisors is an integer number (29533819770).

Almost surely, 2^661535756616 is an apocalyptic number.

It is an amenable number.

661535756616 is an abundant number, since it is smaller than the sum of its proper divisors (1228628708664).

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

661535756616 is a wasteful number, since it uses less digits than its factorization.

661535756616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129814 (or 129810 counting only the distinct ones).

The product of its digits is 20412000, while the sum is 57.

The spelling of 661535756616 in words is "six hundred sixty-one billion, five hundred thirty-five million, seven hundred fifty-six thousand, six hundred sixteen".