661515257712 has 40 divisors (see below), whose sum is σ = 1783215045504. Its totient is φ = 210917907904.

The previous prime is 661515257707. The next prime is 661515257743. The reversal of 661515257712 is 217752515166.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 299598198 + ... + 299600405.

Almost surely, 2^661515257712 is an apocalyptic number.

It is an amenable number.

661515257712 is an abundant number, since it is smaller than the sum of its proper divisors (1121699787792).

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

661515257712 is a wasteful number, since it uses less digits than its factorization.

661515257712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599198637 (or 599198631 counting only the distinct ones).

The product of its digits is 882000, while the sum is 48.

The spelling of 661515257712 in words is "six hundred sixty-one billion, five hundred fifteen million, two hundred fifty-seven thousand, seven hundred twelve".