661560665179 has 2 divisors, whose sum is σ = 661560665180. Its totient is φ = 661560665178.

The previous prime is 661560665173. The next prime is 661560665261. The reversal of 661560665179 is 971566065166.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661560665179 is a prime.

It is not a weakly prime, because it can be changed into another prime (661560665173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330780332589 + 330780332590.

It is an arithmetic number, because the mean of its divisors is an integer number (330780332590).

Almost surely, 2^661560665179 is an apocalyptic number.

661560665179 is a deficient number, since it is larger than the sum of its proper divisors (1).

661560665179 is an equidigital number, since it uses as much as digits as its factorization.

661560665179 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12247200, while the sum is 58.

The spelling of 661560665179 in words is "six hundred sixty-one billion, five hundred sixty million, six hundred sixty-five thousand, one hundred seventy-nine".