91287137 has 2 divisors, whose sum is σ = 91287138. Its totient is φ = 91287136.

The previous prime is 91287109. The next prime is 91287139. The reversal of 91287137 is 73178219.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91221601 + 65536 = 9551^2 + 256^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91287137 is a prime.

Together with 91287139, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91287137.

It is not a weakly prime, because it can be changed into another prime (91287139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45643568 + 45643569.

It is an arithmetic number, because the mean of its divisors is an integer number (45643569).

Almost surely, 2^91287137 is an apocalyptic number.

It is an amenable number.

91287137 is a deficient number, since it is larger than the sum of its proper divisors (1).

91287137 is an equidigital number, since it uses as much as digits as its factorization.

91287137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 38.

The square root of 91287137 is about 9554.4302289566. The cubic root of 91287137 is about 450.2667340453.

The spelling of 91287137 in words is "ninety-one million, two hundred eighty-seven thousand, one hundred thirty-seven".