394804981 has 2 divisors, whose sum is σ = 394804982. Its totient is φ = 394804980.

The previous prime is 394804967. The next prime is 394805017. The reversal of 394804981 is 189408493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 250588900 + 144216081 = 15830^2 + 12009^2 .

It is an emirp because it is prime and its reverse (189408493) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 394804981 - 2²¹ = 392707829 is a prime.

It is a super-2 number, since 2×394804981² = 311741946044820722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (394804181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197402490 + 197402491.

It is an arithmetic number, because the mean of its divisors is an integer number (197402491).

Almost surely, 2^394804981 is an apocalyptic number.

It is an amenable number.

394804981 is a deficient number, since it is larger than the sum of its proper divisors (1).

394804981 is an equidigital number, since it uses as much as digits as its factorization.

394804981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 394804981 is about 19869.7000732271. The cubic root of 394804981 is about 733.6026211897.

The spelling of 394804981 in words is "three hundred ninety-four million, eight hundred four thousand, nine hundred eighty-one".