688739642 has 8 divisors (see below), whose sum is σ = 1039081716. Its totient is φ = 342379072.

The previous prime is 688739641. The next prime is 688739657. The reversal of 688739642 is 246937886.

It can be written as a sum of positive squares in 2 ways, for example, as 550418521 + 138321121 = 23461^2 + 11761^2 .

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 (688739641) 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, 994943 + ... + 995634.

Almost surely, 2^688739642 is an apocalyptic number.

688739642 is a deficient number, since it is larger than the sum of its proper divisors (350342074).

688739642 is a wasteful number, since it uses less digits than its factorization.

688739642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1990752.

The product of its digits is 3483648, while the sum is 53.

The square root of 688739642 is about 26243.8496032880. The cubic root of 688739642 is about 883.1172341754.

The spelling of 688739642 in words is "six hundred eighty-eight million, seven hundred thirty-nine thousand, six hundred forty-two".