681679936 has 56 divisors (see below), whose sum is σ = 1550960576. Its totient is φ = 291202560.

The previous prime is 681679931. The next prime is 681679961. The reversal of 681679936 is 639976186.

It is a tau number, because it is divible by the number of its divisors (56).

It is not an unprimeable number, because it can be changed into a prime (681679931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 145990 + ... + 150586.

Almost surely, 2^681679936 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 681679936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (775480288).

681679936 is an abundant number, since it is smaller than the sum of its proper divisors (869280640).

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

681679936 is a wasteful number, since it uses less digits than its factorization.

681679936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4947 (or 4937 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 55.

The square root of 681679936 is about 26109.0010532766. The cubic root of 681679936 is about 880.0894950304.

Subtracting from 681679936 its sum of digits (55), we obtain a square (681679881 = 26109²).

The spelling of 681679936 in words is "six hundred eighty-one million, six hundred seventy-nine thousand, nine hundred thirty-six".