91040657 has 4 divisors (see below), whose sum is σ = 94180020. Its totient is φ = 87901296.

The previous prime is 91040641. The next prime is 91040671. The reversal of 91040657 is 75604019.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75604019 = 43 ⋅1758233.

It can be written as a sum of positive squares in 2 ways, for example, as 24960016 + 66080641 = 4996^2 + 8129^2 .

It is a cyclic number.

It is not a de Polignac number, because 91040657 - 2⁴ = 91040641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91040617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1569638 + ... + 1569695.

It is an arithmetic number, because the mean of its divisors is an integer number (23545005).

Almost surely, 2^91040657 is an apocalyptic number.

It is an amenable number.

91040657 is a deficient number, since it is larger than the sum of its proper divisors (3139363).

91040657 is a wasteful number, since it uses less digits than its factorization.

91040657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3139362.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 91040657 is about 9541.5227820301. The cubic root of 91040657 is about 449.8611209295.

The spelling of 91040657 in words is "ninety-one million, forty thousand, six hundred fifty-seven".