397478981 has 2 divisors, whose sum is σ = 397478982. Its totient is φ = 397478980.

The previous prime is 397478947. The next prime is 397479011. The reversal of 397478981 is 189874793.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 288694081 + 108784900 = 16991^2 + 10430^2 .

It is an emirp because it is prime and its reverse (189874793) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 397478981 - 2¹⁸ = 397216837 is a prime.

It is a super-2 number, since 2×397478981² = 315979080673596722, 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 (397478281) 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, 198739490 + 198739491.

It is an arithmetic number, because the mean of its divisors is an integer number (198739491).

Almost surely, 2^397478981 is an apocalyptic number.

It is an amenable number.

397478981 is a deficient number, since it is larger than the sum of its proper divisors (1).

397478981 is an equidigital number, since it uses as much as digits as its factorization.

397478981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3048192, while the sum is 56.

The square root of 397478981 is about 19936.8749055613. The cubic root of 397478981 is about 735.2551174487.

The spelling of 397478981 in words is "three hundred ninety-seven million, four hundred seventy-eight thousand, nine hundred eighty-one".