391059978 has 64 divisors (see below), whose sum is σ = 830656512. Its totient is φ = 122567040.

The previous prime is 391059971. The next prime is 391059979. The reversal of 391059978 is 879950193.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 391059978.

It is not an unprimeable number, because it can be changed into a prime (391059971) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1126801 + ... + 1127147.

It is an arithmetic number, because the mean of its divisors is an integer number (12979008).

Almost surely, 2^391059978 is an apocalyptic number.

391059978 is an abundant number, since it is smaller than the sum of its proper divisors (439596534).

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

391059978 is a wasteful number, since it uses less digits than its factorization.

391059978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539.

The product of its (nonzero) digits is 612360, while the sum is 51.

The square root of 391059978 is about 19775.2364840474. The cubic root of 391059978 is about 731.2756690237.

The spelling of 391059978 in words is "three hundred ninety-one million, fifty-nine thousand, nine hundred seventy-eight".