397312978 has 4 divisors (see below), whose sum is σ = 595969470. Its totient is φ = 198656488.

The previous prime is 397312973. The next prime is 397312987. The reversal of 397312978 is 879213793.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 879213793 = 29 ⋅30317717.

It can be written as a sum of positive squares in only one way, i.e., 323748049 + 73564929 = 17993^2 + 8577^2 .

It is a super-3 number, since 3×397312978³ (a number of 27 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (397312973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99328243 + ... + 99328246.

Almost surely, 2^397312978 is an apocalyptic number.

397312978 is a deficient number, since it is larger than the sum of its proper divisors (198656492).

397312978 is a wasteful number, since it uses less digits than its factorization.

397312978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198656491.

The product of its digits is 571536, while the sum is 49.

The square root of 397312978 is about 19932.7112556220. The cubic root of 397312978 is about 735.1527459551.

The spelling of 397312978 in words is "three hundred ninety-seven million, three hundred twelve thousand, nine hundred seventy-eight".