688868786 has 4 divisors (see below), whose sum is σ = 1033303182. Its totient is φ = 344434392.

The previous prime is 688868771. The next prime is 688868809. The reversal of 688868786 is 687868886.

688868786 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 687868886 = 2 ⋅343934443.

It can be written as a sum of positive squares in only one way, i.e., 534488161 + 154380625 = 23119^2 + 12425^2 .

It is a super-2 number, since 2×688868786² = 949080408650227592, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172217195 + ... + 172217198.

Almost surely, 2^688868786 is an apocalyptic number.

688868786 is a deficient number, since it is larger than the sum of its proper divisors (344434396).

688868786 is a wasteful number, since it uses less digits than its factorization.

688868786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344434395.

The product of its digits is 49545216, while the sum is 65.

The square root of 688868786 is about 26246.3099501625. The cubic root of 688868786 is about 883.1724278255.

The spelling of 688868786 in words is "six hundred eighty-eight million, eight hundred sixty-eight thousand, seven hundred eighty-six".