391218974 has 4 divisors (see below), whose sum is σ = 586828464. Its totient is φ = 195609486.

The previous prime is 391218973. The next prime is 391218979. The reversal of 391218974 is 479812193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 479812193 = 7 ⋅68544599.

It is a super-2 number, since 2×391218974² = 306104571235225352, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391218973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97804742 + ... + 97804745.

It is an arithmetic number, because the mean of its divisors is an integer number (146707116).

Almost surely, 2^391218974 is an apocalyptic number.

391218974 is a deficient number, since it is larger than the sum of its proper divisors (195609490).

391218974 is a wasteful number, since it uses less digits than its factorization.

391218974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195609489.

The product of its digits is 108864, while the sum is 44.

The square root of 391218974 is about 19779.2561538598. The cubic root of 391218974 is about 731.3747622224.

The spelling of 391218974 in words is "three hundred ninety-one million, two hundred eighteen thousand, nine hundred seventy-four".