91977913 has 2 divisors, whose sum is σ = 91977914. Its totient is φ = 91977912.

The previous prime is 91977901. The next prime is 91977929. The reversal of 91977913 is 31977919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 89927289 + 2050624 = 9483^2 + 1432^2 .

It is an emirp because it is prime and its reverse (31977919) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91977913 - 2⁵ = 91977881 is a prime.

It is not a weakly prime, because it can be changed into another prime (91977013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45988956 + 45988957.

It is an arithmetic number, because the mean of its divisors is an integer number (45988957).

Almost surely, 2^91977913 is an apocalyptic number.

It is an amenable number.

91977913 is a deficient number, since it is larger than the sum of its proper divisors (1).

91977913 is an equidigital number, since it uses as much as digits as its factorization.

91977913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 107163, while the sum is 46.

The square root of 91977913 is about 9590.5116130476. The cubic root of 91977913 is about 451.3996143471.

The spelling of 91977913 in words is "ninety-one million, nine hundred seventy-seven thousand, nine hundred thirteen".