99998891 has 2 divisors, whose sum is σ = 99998892. Its totient is φ = 99998890.

The previous prime is 99998869. The next prime is 99998909. The reversal of 99998891 is 19889999.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 99998891 - 2¹⁰ = 99997867 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (99998851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49999445 + 49999446.

It is an arithmetic number, because the mean of its divisors is an integer number (49999446).

Almost surely, 2^99998891 is an apocalyptic number.

99998891 is a deficient number, since it is larger than the sum of its proper divisors (1).

99998891 is an equidigital number, since it uses as much as digits as its factorization.

99998891 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 99998891 is about 9999.9445498463. The cubic root of 99998891 is about 464.1571675143.

The spelling of 99998891 in words is "ninety-nine million, nine hundred ninety-eight thousand, eight hundred ninety-one".