681839740 has 48 divisors (see below), whose sum is σ = 1529593632. Its totient is φ = 254406656.

The previous prime is 681839731. The next prime is 681839747. The reversal of 681839740 is 47938186.

It is a happy number.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681839747) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29547 + ... + 47293.

It is an arithmetic number, because the mean of its divisors is an integer number (31866534).

Almost surely, 2^681839740 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681839740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (764796816).

681839740 is an abundant number, since it is smaller than the sum of its proper divisors (847753892).

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

681839740 is a wasteful number, since it uses less digits than its factorization.

681839740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17886 (or 17884 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 46.

The square root of 681839740 is about 26112.0611978450. The cubic root of 681839740 is about 880.1582618253.

The spelling of 681839740 in words is "six hundred eighty-one million, eight hundred thirty-nine thousand, seven hundred forty".