91907405561 has 2 divisors, whose sum is σ = 91907405562. Its totient is φ = 91907405560.

The previous prime is 91907405539. The next prime is 91907405581. The reversal of 91907405561 is 16550470919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47456008336 + 44451397225 = 217844^2 + 210835^2 .

It is an emirp because it is prime and its reverse (16550470919) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91907405561 - 2³⁰ = 90833663737 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (91907405581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45953702780 + 45953702781.

It is an arithmetic number, because the mean of its divisors is an integer number (45953702781).

Almost surely, 2^91907405561 is an apocalyptic number.

It is an amenable number.

91907405561 is a deficient number, since it is larger than the sum of its proper divisors (1).

91907405561 is an equidigital number, since it uses as much as digits as its factorization.

91907405561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 340200, while the sum is 47.

The spelling of 91907405561 in words is "ninety-one billion, nine hundred seven million, four hundred five thousand, five hundred sixty-one".