91028831 has 2 divisors, whose sum is σ = 91028832. Its totient is φ = 91028830.

The previous prime is 91028827. The next prime is 91028879. The reversal of 91028831 is 13882019.

It is a weak prime.

It is an emirp because it is prime and its reverse (13882019) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91028831 - 2² = 91028827 is a prime.

It is a super-2 number, since 2×91028831² = 16572496146453122, which 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 (91028891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45514415 + 45514416.

It is an arithmetic number, because the mean of its divisors is an integer number (45514416).

Almost surely, 2^91028831 is an apocalyptic number.

91028831 is a deficient number, since it is larger than the sum of its proper divisors (1).

91028831 is an equidigital number, since it uses as much as digits as its factorization.

91028831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 91028831 is about 9540.9030495022. The cubic root of 91028831 is about 449.8416413982.

The spelling of 91028831 in words is "ninety-one million, twenty-eight thousand, eight hundred thirty-one".