91998859 has 2 divisors, whose sum is σ = 91998860. Its totient is φ = 91998858.

The previous prime is 91998857. The next prime is 91998869. The reversal of 91998859 is 95889919.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (95889919) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91998859 - 2¹ = 91998857 is a prime.

Together with 91998857, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (91998857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45999429 + 45999430.

It is an arithmetic number, because the mean of its divisors is an integer number (45999430).

Almost surely, 2^91998859 is an apocalyptic number.

91998859 is a deficient number, since it is larger than the sum of its proper divisors (1).

91998859 is an equidigital number, since it uses as much as digits as its factorization.

91998859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2099520, while the sum is 58.

The square root of 91998859 is about 9591.6035677044. The cubic root of 91998859 is about 451.4338772782.

The spelling of 91998859 in words is "ninety-one million, nine hundred ninety-eight thousand, eight hundred fifty-nine".