999898391 has 2 divisors, whose sum is σ = 999898392. Its totient is φ = 999898390.

The previous prime is 999898387. The next prime is 999898399. The reversal of 999898391 is 193898999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999898391 - 2² = 999898387 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999898399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499949195 + 499949196.

It is an arithmetic number, because the mean of its divisors is an integer number (499949196).

Almost surely, 2^999898391 is an apocalyptic number.

999898391 is a deficient number, since it is larger than the sum of its proper divisors (1).

999898391 is an equidigital number, since it uses as much as digits as its factorization.

999898391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11337408, while the sum is 65.

The square root of 999898391 is about 31621.1699815171. The cubic root of 999898391 is about 999.9661291861.

The spelling of 999898391 in words is "nine hundred ninety-nine million, eight hundred ninety-eight thousand, three hundred ninety-one".