688681566 has 12 divisors (see below), whose sum is σ = 1492143432. Its totient is φ = 229560516.

The previous prime is 688681561. The next prime is 688681583. The reversal of 688681566 is 665186886.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688681561) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19130026 + ... + 19130061.

It is an arithmetic number, because the mean of its divisors is an integer number (124345286).

Almost surely, 2^688681566 is an apocalyptic number.

688681566 is an abundant number, since it is smaller than the sum of its proper divisors (803461866).

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

688681566 is a wasteful number, since it uses less digits than its factorization.

688681566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38260095 (or 38260092 counting only the distinct ones).

The product of its digits is 3317760, while the sum is 54.

The square root of 688681566 is about 26242.7431111917. The cubic root of 688681566 is about 883.0924113662.

The spelling of 688681566 in words is "six hundred eighty-eight million, six hundred eighty-one thousand, five hundred sixty-six".