398005381 has 2 divisors, whose sum is σ = 398005382. Its totient is φ = 398005380.

The previous prime is 398005319. The next prime is 398005423. The reversal of 398005381 is 183500893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 290157156 + 107848225 = 17034^2 + 10385^2 .

It is a cyclic number.

It is not a de Polignac number, because 398005381 - 2¹⁹ = 397481093 is a prime.

It is a super-2 number, since 2×398005381² = 316816566609910322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 398005381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398005981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199002690 + 199002691.

It is an arithmetic number, because the mean of its divisors is an integer number (199002691).

Almost surely, 2^398005381 is an apocalyptic number.

It is an amenable number.

398005381 is a deficient number, since it is larger than the sum of its proper divisors (1).

398005381 is an equidigital number, since it uses as much as digits as its factorization.

398005381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 398005381 is about 19950.0722053831. The cubic root of 398005381 is about 735.5795518467.

The spelling of 398005381 in words is "three hundred ninety-eight million, five thousand, three hundred eighty-one".