661759967923 has 2 divisors, whose sum is σ = 661759967924. Its totient is φ = 661759967922.

The previous prime is 661759967857. The next prime is 661759967933. The reversal of 661759967923 is 329769957166.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661759967923 is a prime.

It is not a weakly prime, because it can be changed into another prime (661759967933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330879983961 + 330879983962.

It is an arithmetic number, because the mean of its divisors is an integer number (330879983962).

Almost surely, 2^661759967923 is an apocalyptic number.

661759967923 is a deficient number, since it is larger than the sum of its proper divisors (1).

661759967923 is an equidigital number, since it uses as much as digits as its factorization.

661759967923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 231472080, while the sum is 70.

The spelling of 661759967923 in words is "six hundred sixty-one billion, seven hundred fifty-nine million, nine hundred sixty-seven thousand, nine hundred twenty-three".