398435981 has 2 divisors, whose sum is σ = 398435982. Its totient is φ = 398435980.

The previous prime is 398435977. The next prime is 398436029. The reversal of 398435981 is 189534893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 360810025 + 37625956 = 18995^2 + 6134^2 .

It is a cyclic number.

It is not a de Polignac number, because 398435981 - 2² = 398435977 is a prime.

It is a super-2 number, since 2×398435981² = 317502461910864722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398435951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199217990 + 199217991.

It is an arithmetic number, because the mean of its divisors is an integer number (199217991).

Almost surely, 2^398435981 is an apocalyptic number.

It is an amenable number.

398435981 is a deficient number, since it is larger than the sum of its proper divisors (1).

398435981 is an equidigital number, since it uses as much as digits as its factorization.

398435981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 933120, while the sum is 50.

The square root of 398435981 is about 19960.8612289149. The cubic root of 398435981 is about 735.8447294985.

The spelling of 398435981 in words is "three hundred ninety-eight million, four hundred thirty-five thousand, nine hundred eighty-one".