998149891 has 2 divisors, whose sum is σ = 998149892. Its totient is φ = 998149890.

The previous prime is 998149877. The next prime is 998149909. The reversal of 998149891 is 198941899.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 998149891 - 2⁹ = 998149379 is a prime.

It is not a weakly prime, because it can be changed into another prime (998141891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499074945 + 499074946.

It is an arithmetic number, because the mean of its divisors is an integer number (499074946).

Almost surely, 2^998149891 is an apocalyptic number.

998149891 is a deficient number, since it is larger than the sum of its proper divisors (1).

998149891 is an equidigital number, since it uses as much as digits as its factorization.

998149891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1679616, while the sum is 58.

The square root of 998149891 is about 31593.5102671419. The cubic root of 998149891 is about 999.3829162860.

The spelling of 998149891 in words is "nine hundred ninety-eight million, one hundred forty-nine thousand, eight hundred ninety-one".