394172381 has 2 divisors, whose sum is σ = 394172382. Its totient is φ = 394172380.

The previous prime is 394172377. The next prime is 394172399. The reversal of 394172381 is 183271493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 370562500 + 23609881 = 19250^2 + 4859^2 .

It is a cyclic number.

It is not a de Polignac number, because 394172381 - 2² = 394172377 is a prime.

It is a super-2 number, since 2×394172381² = 310743731886418322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (394172341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197086190 + 197086191.

It is an arithmetic number, because the mean of its divisors is an integer number (197086191).

Almost surely, 2^394172381 is an apocalyptic number.

It is an amenable number.

394172381 is a deficient number, since it is larger than the sum of its proper divisors (1).

394172381 is an equidigital number, since it uses as much as digits as its factorization.

394172381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 394172381 is about 19853.7749810962. The cubic root of 394172381 is about 733.2105921066.

The spelling of 394172381 in words is "three hundred ninety-four million, one hundred seventy-two thousand, three hundred eighty-one".