688138874 has 8 divisors (see below), whose sum is σ = 1032375540. Its totient is φ = 344013696.

The previous prime is 688138859. The next prime is 688138879. The reversal of 688138874 is 478831886.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 589275625 + 98863249 = 24275^2 + 9943^2 .

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

It is not an unprimeable number, because it can be changed into a prime (688138879) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10199 + ... + 38474.

Almost surely, 2^688138874 is an apocalyptic number.

688138874 is a deficient number, since it is larger than the sum of its proper divisors (344236666).

688138874 is a wasteful number, since it uses less digits than its factorization.

688138874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55744.

The product of its digits is 2064384, while the sum is 53.

The square root of 688138874 is about 26232.4012244400. The cubic root of 688138874 is about 882.8603867990.

The spelling of 688138874 in words is "six hundred eighty-eight million, one hundred thirty-eight thousand, eight hundred seventy-four".