661687720076 has 12 divisors (see below), whose sum is σ = 1170964224360. Its totient is φ = 327126513120.

The previous prime is 661687720073. The next prime is 661687720091. The reversal of 661687720076 is 670027786166.

It is not an unprimeable number, because it can be changed into a prime (661687720073) 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, 929336330 + ... + 929337041.

It is an arithmetic number, because the mean of its divisors is an integer number (97580352030).

Almost surely, 2^661687720076 is an apocalyptic number.

It is an amenable number.

661687720076 is a deficient number, since it is larger than the sum of its proper divisors (509276504284).

661687720076 is a wasteful number, since it uses less digits than its factorization.

661687720076 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1858673464 (or 1858673462 counting only the distinct ones).

The product of its (nonzero) digits is 7112448, while the sum is 56.

The spelling of 661687720076 in words is "six hundred sixty-one billion, six hundred eighty-seven million, seven hundred twenty thousand, seventy-six".