661047057091 has 2 divisors, whose sum is σ = 661047057092. Its totient is φ = 661047057090.

The previous prime is 661047057031. The next prime is 661047057149. The reversal of 661047057091 is 190750740166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661047057091 - 2⁷ = 661047056963 is a prime.

It is not a weakly prime, because it can be changed into another prime (661047057031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330523528545 + 330523528546.

It is an arithmetic number, because the mean of its divisors is an integer number (330523528546).

Almost surely, 2^661047057091 is an apocalyptic number.

661047057091 is a deficient number, since it is larger than the sum of its proper divisors (1).

661047057091 is an equidigital number, since it uses as much as digits as its factorization.

661047057091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 317520, while the sum is 46.

The spelling of 661047057091 in words is "six hundred sixty-one billion, forty-seven million, fifty-seven thousand, ninety-one".