688768957 has 4 divisors (see below), whose sum is σ = 729284796. Its totient is φ = 648253120.

The previous prime is 688768903. The next prime is 688768979. The reversal of 688768957 is 759867886.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 759867886 = 2 ⋅379933943.

It can be written as a sum of positive squares in 2 ways, for example, as 460789156 + 227979801 = 21466^2 + 15099^2 .

It is a cyclic number.

It is not a de Polignac number, because 688768957 - 2¹¹ = 688766909 is a prime.

It is a super-2 number, since 2×688768957² = 948805352253735698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688768987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20257894 + ... + 20257927.

It is an arithmetic number, because the mean of its divisors is an integer number (182321199).

Almost surely, 2^688768957 is an apocalyptic number.

It is an amenable number.

688768957 is a deficient number, since it is larger than the sum of its proper divisors (40515839).

688768957 is a wasteful number, since it uses less digits than its factorization.

688768957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40515838.

The product of its digits is 40642560, while the sum is 64.

The square root of 688768957 is about 26244.4081091573. The cubic root of 688768957 is about 883.1297634452.

It can be divided in two parts, 688768 and 957, that added together give a triangular number (689725 = T₁₁₇₄).

The spelling of 688768957 in words is "six hundred eighty-eight million, seven hundred sixty-eight thousand, nine hundred fifty-seven".