393978 has 16 divisors (see below), whose sum is σ = 848736. Its totient is φ = 121200.

The previous prime is 393977. The next prime is 393989. The reversal of 393978 is 879393.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (393977) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2448 + ... + 2603.

It is an arithmetic number, because the mean of its divisors is an integer number (53046).

2³⁹³⁹⁷⁸ is an apocalyptic number.

393978 is an abundant number, since it is smaller than the sum of its proper divisors (454758).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

393978 is a wasteful number, since it uses less digits than its factorization.

393978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5069.

The product of its digits is 40824, while the sum is 39.

The square root of 393978 is about 627.6766683572. The cubic root of 393978 is about 73.3090047857.

The spelling of 393978 in words is "three hundred ninety-three thousand, nine hundred seventy-eight".