394921081 has 2 divisors, whose sum is σ = 394921082. Its totient is φ = 394921080.

The previous prime is 394921069. The next prime is 394921103. The reversal of 394921081 is 180129493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 209525625 + 185395456 = 14475^2 + 13616^2 .

It is an emirp because it is prime and its reverse (180129493) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 394921081 - 2⁵ = 394921049 is a prime.

It is a super-2 number, since 2×394921081² = 311925320436417122, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 394921081.

It is not a weakly prime, because it can be changed into another prime (394921001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197460540 + 197460541.

It is an arithmetic number, because the mean of its divisors is an integer number (197460541).

Almost surely, 2^394921081 is an apocalyptic number.

It is an amenable number.

394921081 is a deficient number, since it is larger than the sum of its proper divisors (1).

394921081 is an equidigital number, since it uses as much as digits as its factorization.

394921081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 394921081 is about 19872.6213922572. The cubic root of 394921081 is about 733.6745241300.

The spelling of 394921081 in words is "three hundred ninety-four million, nine hundred twenty-one thousand, eighty-one".