397637818 has 4 divisors (see below), whose sum is σ = 596456730. Its totient is φ = 198818908.

The previous prime is 397637797. The next prime is 397637857. The reversal of 397637818 is 818736793.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 818736793 = 7 ⋅116962399.

It can be written as a sum of positive squares in only one way, i.e., 380523049 + 17114769 = 19507^2 + 4137^2 .

It is a super-2 number, since 2×397637818² = 316231668607602248, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99409453 + ... + 99409456.

Almost surely, 2^397637818 is an apocalyptic number.

397637818 is a deficient number, since it is larger than the sum of its proper divisors (198818912).

397637818 is a wasteful number, since it uses less digits than its factorization.

397637818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198818911.

The product of its digits is 1524096, while the sum is 52.

The square root of 397637818 is about 19940.8580056125. The cubic root of 397637818 is about 735.3530431000.

The spelling of 397637818 in words is "three hundred ninety-seven million, six hundred thirty-seven thousand, eight hundred eighteen".