397191566 has 8 divisors (see below), whose sum is σ = 596292840. Its totient is φ = 198427288.

The previous prime is 397191563. The next prime is 397191589. The reversal of 397191566 is 665191793.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×397191566² = 315522280203064712, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 397191566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (397191563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81281 + ... + 86028.

It is an arithmetic number, because the mean of its divisors is an integer number (74536605).

Almost surely, 2^397191566 is an apocalyptic number.

397191566 is a deficient number, since it is larger than the sum of its proper divisors (199101274).

397191566 is a wasteful number, since it uses less digits than its factorization.

397191566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168498.

The product of its digits is 306180, while the sum is 47.

The square root of 397191566 is about 19929.6654763696. The cubic root of 397191566 is about 735.0778549889.

The spelling of 397191566 in words is "three hundred ninety-seven million, one hundred ninety-one thousand, five hundred sixty-six".