688735866 has 96 divisors (see below), whose sum is σ = 1781595648. Its totient is φ = 175754880.

The previous prime is 688735849. The next prime is 688735891. The reversal of 688735866 is 668537886.

It is a happy number.

It is a super-2 number, since 2×688735866² = 948714186229539912, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 115576 + ... + 121388.

It is an arithmetic number, because the mean of its divisors is an integer number (18558288).

Almost surely, 2^688735866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 688735866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (890797824).

688735866 is an abundant number, since it is smaller than the sum of its proper divisors (1092859782).

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

688735866 is a wasteful number, since it uses less digits than its factorization.

688735866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5876 (or 5869 counting only the distinct ones).

The product of its digits is 11612160, while the sum is 57.

The square root of 688735866 is about 26243.7776625241. Note that the first 3 decimals coincide. The cubic root of 688735866 is about 883.1156202821.

The spelling of 688735866 in words is "six hundred eighty-eight million, seven hundred thirty-five thousand, eight hundred sixty-six".