91550591831 has 2 divisors, whose sum is σ = 91550591832. Its totient is φ = 91550591830.

The previous prime is 91550591813. The next prime is 91550591837. The reversal of 91550591831 is 13819505519.

It is a happy number.

Together with previous prime (91550591813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is an emirp because it is prime and its reverse (13819505519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91550591831 - 2⁶ = 91550591767 is a prime.

It is a super-2 number, since 2×91550591831² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91550591837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45775295915 + 45775295916.

It is an arithmetic number, because the mean of its divisors is an integer number (45775295916).

Almost surely, 2^91550591831 is an apocalyptic number.

91550591831 is a deficient number, since it is larger than the sum of its proper divisors (1).

91550591831 is an equidigital number, since it uses as much as digits as its factorization.

91550591831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 243000, while the sum is 47.

The spelling of 91550591831 in words is "ninety-one billion, five hundred fifty million, five hundred ninety-one thousand, eight hundred thirty-one".