661759967994 has 16 divisors (see below), whose sum is σ = 1323552584640. Its totient is φ = 220581214560.

The previous prime is 661759967977. The next prime is 661759968007. The reversal of 661759967994 is 499769957166.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1092814 + ... + 1586745.

It is an arithmetic number, because the mean of its divisors is an integer number (82722036540).

Almost surely, 2^661759967994 is an apocalyptic number.

661759967994 is an abundant number, since it is smaller than the sum of its proper divisors (661792616646).

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

661759967994 is a wasteful number, since it uses less digits than its factorization.

661759967994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2720725.

The product of its digits is 1388832480, while the sum is 78.

The spelling of 661759967994 in words is "six hundred sixty-one billion, seven hundred fifty-nine million, nine hundred sixty-seven thousand, nine hundred ninety-four".