398899681 has 2 divisors, whose sum is σ = 398899682. Its totient is φ = 398899680.

The previous prime is 398899673. The next prime is 398899703. The reversal of 398899681 is 186998893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 235469025 + 163430656 = 15345^2 + 12784^2 .

It is a cyclic number.

It is not a de Polignac number, because 398899681 - 2³ = 398899673 is a prime.

It is a super-2 number, since 2×398899681² = 318241911003803522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (398899621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199449840 + 199449841.

It is an arithmetic number, because the mean of its divisors is an integer number (199449841).

Almost surely, 2^398899681 is an apocalyptic number.

It is an amenable number.

398899681 is a deficient number, since it is larger than the sum of its proper divisors (1).

398899681 is an equidigital number, since it uses as much as digits as its factorization.

398899681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6718464, while the sum is 61.

The square root of 398899681 is about 19972.4730817192. The cubic root of 398899681 is about 736.1300776561.

The spelling of 398899681 in words is "three hundred ninety-eight million, eight hundred ninety-nine thousand, six hundred eighty-one".