688136988 has 72 divisors (see below), whose sum is σ = 2037619584. Its totient is φ = 178735200.

The previous prime is 688136987. The next prime is 688137007. The reversal of 688136988 is 889631886.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688136983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 46728 + ... + 59663.

It is an arithmetic number, because the mean of its divisors is an integer number (28300272).

Almost surely, 2^688136988 is an apocalyptic number.

It is an amenable number.

688136988 is an abundant number, since it is smaller than the sum of its proper divisors (1349482596).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688136988 is a wasteful number, since it uses less digits than its factorization.

688136988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106423 (or 106414 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 57.

The square root of 688136988 is about 26232.3652765053. The cubic root of 688136988 is about 882.8595802389.

The spelling of 688136988 in words is "six hundred eighty-eight million, one hundred thirty-six thousand, nine hundred eighty-eight".