684173978 has 8 divisors (see below), whose sum is σ = 1028900340. Its totient is φ = 341207200.

The previous prime is 684173969. The next prime is 684174013. The reversal of 684173978 is 879371486.

684173978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 683665609 + 508369 = 26147^2 + 713^2 .

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

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, 438923 + ... + 440478.

Almost surely, 2^684173978 is an apocalyptic number.

684173978 is a deficient number, since it is larger than the sum of its proper divisors (344726362).

684173978 is a wasteful number, since it uses less digits than its factorization.

684173978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879792.

The product of its digits is 2032128, while the sum is 53.

The square root of 684173978 is about 26156.7195573145. The cubic root of 684173978 is about 881.1615077515.

The spelling of 684173978 in words is "six hundred eighty-four million, one hundred seventy-three thousand, nine hundred seventy-eight".