399181 has 2 divisors, whose sum is σ = 399182. Its totient is φ = 399180.

The previous prime is 399173. The next prime is 399197. The reversal of 399181 is 181993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 265225 + 133956 = 515^2 + 366^2 .

It is a cyclic number.

It is not a de Polignac number, because 399181 - 2³ = 399173 is a prime.

It is a super-2 number, since 2×399181² = 318690941522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199590 + 199591.

It is an arithmetic number, because the mean of its divisors is an integer number (199591).

2³⁹⁹¹⁸¹ is an apocalyptic number.

It is an amenable number.

399181 is a deficient number, since it is larger than the sum of its proper divisors (1).

399181 is an equidigital number, since it uses as much as digits as its factorization.

399181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 31.

The square root of 399181 is about 631.8077239161. The cubic root of 399181 is about 73.6303085829.

The spelling of 399181 in words is "three hundred ninety-nine thousand, one hundred eighty-one".