688569966 has 48 divisors (see below), whose sum is σ = 1716369408. Its totient is φ = 195426000.

The previous prime is 688569863. The next prime is 688569971. The reversal of 688569966 is 669965886.

688569966 is a `hidden beast` number, since 6 + 8 + 8 + 569 + 9 + 66 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 931 + ... + 37121.

It is an arithmetic number, because the mean of its divisors is an integer number (35757696).

Almost surely, 2^688569966 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 688569966, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (858184704).

688569966 is an abundant number, since it is smaller than the sum of its proper divisors (1027799442).

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

688569966 is a wasteful number, since it uses less digits than its factorization.

688569966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36357 (or 36354 counting only the distinct ones).

The product of its digits is 33592320, while the sum is 63.

The square root of 688569966 is about 26240.6167229355. The cubic root of 688569966 is about 883.0447074433.

The spelling of 688569966 in words is "six hundred eighty-eight million, five hundred sixty-nine thousand, nine hundred sixty-six".