3981909640 has 16 divisors (see below), whose sum is σ = 8959296780. Its totient is φ = 1592763840.

The previous prime is 3981909619. The next prime is 3981909647. The reversal of 3981909640 is 469091893.

It can be written as a sum of positive squares in 2 ways, for example, as 3784956484 + 196953156 = 61522^2 + 14034^2 .

It is a super-2 number, since 2×3981909640² = 31711208762249859200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (3981909647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49773831 + ... + 49773910.

Almost surely, 2^3981909640 is an apocalyptic number.

It is an amenable number.

3981909640 is an abundant number, since it is smaller than the sum of its proper divisors (4977387140).

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

3981909640 is a wasteful number, since it uses less digits than its factorization.

3981909640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99547752 (or 99547748 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 49.

The square root of 3981909640 is about 63102.3742817970. The cubic root of 3981909640 is about 1585.0043805669.

The spelling of 3981909640 in words is "three billion, nine hundred eighty-one million, nine hundred nine thousand, six hundred forty".