91308739657 has 4 divisors (see below), whose sum is σ = 91325176516. Its totient is φ = 91292302800.

The previous prime is 91308739637. The next prime is 91308739667. The reversal of 91308739657 is 75693780319.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 44194130176 + 47114609481 = 210224^2 + 217059^2 .

It is a cyclic number.

It is not a de Polignac number, because 91308739657 - 2¹¹ = 91308737609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91308739607) 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, 8210094 + ... + 8221207.

It is an arithmetic number, because the mean of its divisors is an integer number (22831294129).

Almost surely, 2^91308739657 is an apocalyptic number.

It is an amenable number.

91308739657 is a deficient number, since it is larger than the sum of its proper divisors (16436859).

91308739657 is a wasteful number, since it uses less digits than its factorization.

91308739657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16436858.

The product of its (nonzero) digits is 8573040, while the sum is 58.

The spelling of 91308739657 in words is "ninety-one billion, three hundred eight million, seven hundred thirty-nine thousand, six hundred fifty-seven".