86991913 has 2 divisors, whose sum is σ = 86991914. Its totient is φ = 86991912.

The previous prime is 86991871. The next prime is 86991977. The reversal of 86991913 is 31919968.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68095504 + 18896409 = 8252^2 + 4347^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-86991913 is a prime.

It is not a weakly prime, because it can be changed into another prime (86991013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43495956 + 43495957.

It is an arithmetic number, because the mean of its divisors is an integer number (43495957).

Almost surely, 2^86991913 is an apocalyptic number.

It is an amenable number.

86991913 is a deficient number, since it is larger than the sum of its proper divisors (1).

86991913 is an equidigital number, since it uses as much as digits as its factorization.

86991913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 104976, while the sum is 46.

The square root of 86991913 is about 9326.9455343108. The cubic root of 86991913 is about 443.0910322872.

The spelling of 86991913 in words is "eighty-six million, nine hundred ninety-one thousand, nine hundred thirteen".