91023071537 has 4 divisors (see below), whose sum is σ = 91043664756. Its totient is φ = 91002478320.

The previous prime is 91023071521. The next prime is 91023071609. The reversal of 91023071537 is 73517032019.

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 44553077776 + 46469993761 = 211076^2 + 215569^2 .

It is a cyclic number.

It is not a de Polignac number, because 91023071537 - 2⁴ = 91023071521 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91023071537.

It is not an unprimeable number, because it can be changed into a prime (91023071137) 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, 10289978 + ... + 10298819.

It is an arithmetic number, because the mean of its divisors is an integer number (22760916189).

Almost surely, 2^91023071537 is an apocalyptic number.

It is an amenable number.

91023071537 is a deficient number, since it is larger than the sum of its proper divisors (20593219).

91023071537 is a wasteful number, since it uses less digits than its factorization.

91023071537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20593218.

The product of its (nonzero) digits is 39690, while the sum is 38.

The spelling of 91023071537 in words is "ninety-one billion, twenty-three million, seventy-one thousand, five hundred thirty-seven".