394957561 has 2 divisors, whose sum is σ = 394957562. Its totient is φ = 394957560.

The previous prime is 394957559. The next prime is 394957621. The reversal of 394957561 is 165759493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 384356025 + 10601536 = 19605^2 + 3256^2 .

It is an emirp because it is prime and its reverse (165759493) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 394957561 - 2¹ = 394957559 is a prime.

Together with 394957559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (394957501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197478780 + 197478781.

It is an arithmetic number, because the mean of its divisors is an integer number (197478781).

Almost surely, 2^394957561 is an apocalyptic number.

It is an amenable number.

394957561 is a deficient number, since it is larger than the sum of its proper divisors (1).

394957561 is an equidigital number, since it uses as much as digits as its factorization.

394957561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1020600, while the sum is 49.

The square root of 394957561 is about 19873.5392167575. The cubic root of 394957561 is about 733.6971139789.

The spelling of 394957561 in words is "three hundred ninety-four million, nine hundred fifty-seven thousand, five hundred sixty-one".