394021978 has 8 divisors (see below), whose sum is σ = 675466272. Its totient is φ = 168866556.

The previous prime is 394021961. The next prime is 394021987. The reversal of 394021978 is 879120493.

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

394021978 is a modest number, since divided by 21978 gives 394 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14072200 + ... + 14072227.

It is an arithmetic number, because the mean of its divisors is an integer number (84433284).

Almost surely, 2^394021978 is an apocalyptic number.

394021978 is a deficient number, since it is larger than the sum of its proper divisors (281444294).

394021978 is a wasteful number, since it uses less digits than its factorization.

394021978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28144436.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 394021978 is about 19849.9868513810. The cubic root of 394021978 is about 733.1173240282.

The spelling of 394021978 in words is "three hundred ninety-four million, twenty-one thousand, nine hundred seventy-eight".