398136581 has 2 divisors, whose sum is σ = 398136582. Its totient is φ = 398136580.

The previous prime is 398136559. The next prime is 398136587. The reversal of 398136581 is 185631893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220047556 + 178089025 = 14834^2 + 13345^2 .

It is an emirp because it is prime and its reverse (185631893) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 398136581 - 2¹⁸ = 397874437 is a prime.

It is a super-2 number, since 2×398136581² = 317025474260739122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398136587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199068290 + 199068291.

It is an arithmetic number, because the mean of its divisors is an integer number (199068291).

Almost surely, 2^398136581 is an apocalyptic number.

It is an amenable number.

398136581 is a deficient number, since it is larger than the sum of its proper divisors (1).

398136581 is an equidigital number, since it uses as much as digits as its factorization.

398136581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 44.

The square root of 398136581 is about 19953.3601430937. The cubic root of 398136581 is about 735.6603693761.

The spelling of 398136581 in words is "three hundred ninety-eight million, one hundred thirty-six thousand, five hundred eighty-one".