681923788 has 144 divisors (see below), whose sum is σ = 1604836800. Its totient is φ = 252435456.

The previous prime is 681923783. The next prime is 681923857. The reversal of 681923788 is 887329186.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is not an unprimeable number, because it can be changed into a prime (681923783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3941670 + ... + 3941842.

It is an arithmetic number, because the mean of its divisors is an integer number (11144700).

Almost surely, 2^681923788 is an apocalyptic number.

681923788 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681923788, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (802418400).

681923788 is an abundant number, since it is smaller than the sum of its proper divisors (922913012).

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

681923788 is a wasteful number, since it uses less digits than its factorization.

681923788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241 (or 212 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 52.

The square root of 681923788 is about 26113.6705194808. The cubic root of 681923788 is about 880.1944250163.

The spelling of 681923788 in words is "six hundred eighty-one million, nine hundred twenty-three thousand, seven hundred eighty-eight".