91684391261 has 2 divisors, whose sum is σ = 91684391262. Its totient is φ = 91684391260.

The previous prime is 91684391189. The next prime is 91684391273. The reversal of 91684391261 is 16219348619.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91207624036 + 476767225 = 302006^2 + 21835^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91684391261 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91684396261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45842195630 + 45842195631.

It is an arithmetic number, because the mean of its divisors is an integer number (45842195631).

Almost surely, 2^91684391261 is an apocalyptic number.

It is an amenable number.

91684391261 is a deficient number, since it is larger than the sum of its proper divisors (1).

91684391261 is an equidigital number, since it uses as much as digits as its factorization.

91684391261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 50.

The spelling of 91684391261 in words is "ninety-one billion, six hundred eighty-four million, three hundred ninety-one thousand, two hundred sixty-one".