3681981644 has 12 divisors (see below), whose sum is σ = 7029237768. Its totient is φ = 1673628000.

The previous prime is 3681981637. The next prime is 3681981647. The reversal of 3681981644 is 4461891863.

It is a junction number, because it is equal to n+sod(n) for n = 3681981592 and 3681981601.

It is not an unprimeable number, because it can be changed into a prime (3681981647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41840657 + ... + 41840744.

It is an arithmetic number, because the mean of its divisors is an integer number (585769814).

Almost surely, 2^3681981644 is an apocalyptic number.

It is an amenable number.

3681981644 is a deficient number, since it is larger than the sum of its proper divisors (3347256124).

3681981644 is a wasteful number, since it uses less digits than its factorization.

3681981644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83681416 (or 83681414 counting only the distinct ones).

The product of its digits is 995328, while the sum is 50.

The square root of 3681981644 is about 60679.3345711701. The cubic root of 3681981644 is about 1544.1655991005.

The spelling of 3681981644 in words is "three billion, six hundred eighty-one million, nine hundred eighty-one thousand, six hundred forty-four".