678439990 has 16 divisors (see below), whose sum is σ = 1239419952. Its totient is φ = 267325344.

The previous prime is 678439967. The next prime is 678440023. The reversal of 678439990 is 99934876.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 505629 + ... + 506968.

It is an arithmetic number, because the mean of its divisors is an integer number (77463747).

Almost surely, 2^678439990 is an apocalyptic number.

678439990 is a deficient number, since it is larger than the sum of its proper divisors (560979962).

678439990 is a wasteful number, since it uses less digits than its factorization.

678439990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1012671.

The product of its (nonzero) digits is 2939328, while the sum is 55.

The square root of 678439990 is about 26046.8806193755. The cubic root of 678439990 is about 878.6929589239.

The spelling of 678439990 in words is "six hundred seventy-eight million, four hundred thirty-nine thousand, nine hundred ninety".