99918989 has 2 divisors, whose sum is σ = 99918990. Its totient is φ = 99918988.

The previous prime is 99918977. The next prime is 99919019. The reversal of 99918989 is 98981999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 89453764 + 10465225 = 9458^2 + 3235^2 .

It is a cyclic number.

It is not a de Polignac number, because 99918989 - 2⁸ = 99918733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99918289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49959494 + 49959495.

It is an arithmetic number, because the mean of its divisors is an integer number (49959495).

Almost surely, 2^99918989 is an apocalyptic number.

It is an amenable number.

99918989 is a deficient number, since it is larger than the sum of its proper divisors (1).

99918989 is an equidigital number, since it uses as much as digits as its factorization.

99918989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3779136, while the sum is 62.

The square root of 99918989 is about 9995.9486293198. The cubic root of 99918989 is about 464.0335095820.

The spelling of 99918989 in words is "ninety-nine million, nine hundred eighteen thousand, nine hundred eighty-nine".