91917281 has 2 divisors, whose sum is σ = 91917282. Its totient is φ = 91917280.

The previous prime is 91917277. The next prime is 91917299. The reversal of 91917281 is 18271919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87590881 + 4326400 = 9359^2 + 2080^2 .

It is a cyclic number.

It is not a de Polignac number, because 91917281 - 2² = 91917277 is a prime.

It is a super-2 number, since 2×91917281² = 16897573092865922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (91917481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45958640 + 45958641.

It is an arithmetic number, because the mean of its divisors is an integer number (45958641).

Almost surely, 2^91917281 is an apocalyptic number.

It is an amenable number.

91917281 is a deficient number, since it is larger than the sum of its proper divisors (1).

91917281 is an equidigital number, since it uses as much as digits as its factorization.

91917281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 38.

The square root of 91917281 is about 9587.3500509786. The cubic root of 91917281 is about 451.3004047409.

The spelling of 91917281 in words is "ninety-one million, nine hundred seventeen thousand, two hundred eighty-one".