681681816 has 48 divisors (see below), whose sum is σ = 1905783360. Its totient is φ = 219896640.

The previous prime is 681681779. The next prime is 681681839. The reversal of 681681816 is 618186186.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 150475 + ... + 154938.

It is an arithmetic number, because the mean of its divisors is an integer number (39703820).

Almost surely, 2^681681816 is an apocalyptic number.

It is an amenable number.

681681816 is an abundant number, since it is smaller than the sum of its proper divisors (1224101544).

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

681681816 is a wasteful number, since it uses less digits than its factorization.

681681816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305456 (or 305449 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 681681816 is about 26109.0370561612. The cubic root of 681681816 is about 880.0903040937.

The spelling of 681681816 in words is "six hundred eighty-one million, six hundred eighty-one thousand, eight hundred sixteen".