91816121 has 2 divisors, whose sum is σ = 91816122. Its totient is φ = 91816120.

The previous prime is 91816093. The next prime is 91816147. The reversal of 91816121 is 12161819.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 82446400 + 9369721 = 9080^2 + 3061^2 .

It is a cyclic number.

It is not a de Polignac number, because 91816121 - 2⁶ = 91816057 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (91816181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45908060 + 45908061.

It is an arithmetic number, because the mean of its divisors is an integer number (45908061).

Almost surely, 2^91816121 is an apocalyptic number.

It is an amenable number.

91816121 is a deficient number, since it is larger than the sum of its proper divisors (1).

91816121 is an equidigital number, since it uses as much as digits as its factorization.

91816121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 29.

The square root of 91816121 is about 9582.0728968214. The cubic root of 91816121 is about 451.1347837000.

The spelling of 91816121 in words is "ninety-one million, eight hundred sixteen thousand, one hundred twenty-one".