91378817 has 2 divisors, whose sum is σ = 91378818. Its totient is φ = 91378816.

The previous prime is 91378813. The next prime is 91378829. The reversal of 91378817 is 71887319.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75186241 + 16192576 = 8671^2 + 4024^2 .

It is a cyclic number.

It is not a de Polignac number, because 91378817 - 2² = 91378813 is a prime.

It is not a weakly prime, because it can be changed into another prime (91378813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45689408 + 45689409.

It is an arithmetic number, because the mean of its divisors is an integer number (45689409).

Almost surely, 2^91378817 is an apocalyptic number.

It is an amenable number.

91378817 is a deficient number, since it is larger than the sum of its proper divisors (1).

91378817 is an equidigital number, since it uses as much as digits as its factorization.

91378817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 44.

The square root of 91378817 is about 9559.2267992762. The cubic root of 91378817 is about 450.4174184457.

The spelling of 91378817 in words is "ninety-one million, three hundred seventy-eight thousand, eight hundred seventeen".