91904608813 has 2 divisors, whose sum is σ = 91904608814. Its totient is φ = 91904608812.

The previous prime is 91904608801. The next prime is 91904608843. The reversal of 91904608813 is 31880640919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51985368009 + 39919240804 = 228003^2 + 199798^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91904608813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91904608843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45952304406 + 45952304407.

It is an arithmetic number, because the mean of its divisors is an integer number (45952304407).

Almost surely, 2^91904608813 is an apocalyptic number.

It is an amenable number.

91904608813 is a deficient number, since it is larger than the sum of its proper divisors (1).

91904608813 is an equidigital number, since it uses as much as digits as its factorization.

91904608813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 49.

The spelling of 91904608813 in words is "ninety-one billion, nine hundred four million, six hundred eight thousand, eight hundred thirteen".