91830931987 has 2 divisors, whose sum is σ = 91830931988. Its totient is φ = 91830931986.

The previous prime is 91830931981. The next prime is 91830932009. The reversal of 91830931987 is 78913903819.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91830931987 is a prime.

It is not a weakly prime, because it can be changed into another prime (91830931981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45915465993 + 45915465994.

It is an arithmetic number, because the mean of its divisors is an integer number (45915465994).

Almost surely, 2^91830931987 is an apocalyptic number.

91830931987 is a deficient number, since it is larger than the sum of its proper divisors (1).

91830931987 is an equidigital number, since it uses as much as digits as its factorization.

91830931987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2939328, while the sum is 58.

The spelling of 91830931987 in words is "ninety-one billion, eight hundred thirty million, nine hundred thirty-one thousand, nine hundred eighty-seven".