91916381 has 2 divisors, whose sum is σ = 91916382. Its totient is φ = 91916380.

The previous prime is 91916323. The next prime is 91916393. The reversal of 91916381 is 18361919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55204900 + 36711481 = 7430^2 + 6059^2 .

It is a cyclic number.

It is not a de Polignac number, because 91916381 - 2²² = 87722077 is a prime.

It is a super-2 number, since 2×91916381² = 16897242192274322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91919381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45958190 + 45958191.

It is an arithmetic number, because the mean of its divisors is an integer number (45958191).

Almost surely, 2^91916381 is an apocalyptic number.

It is an amenable number.

91916381 is a deficient number, since it is larger than the sum of its proper divisors (1).

91916381 is an equidigital number, since it uses as much as digits as its factorization.

91916381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 38.

The square root of 91916381 is about 9587.3031140149. The cubic root of 91916381 is about 451.2989317800.

The spelling of 91916381 in words is "ninety-one million, nine hundred sixteen thousand, three hundred eighty-one".