3981440 has 32 divisors (see below), whose sum is σ = 9519660. Its totient is φ = 1592320.

The previous prime is 3981421. The next prime is 3981449. The reversal of 3981440 is 441893.

It can be written as a sum of positive squares in 2 ways, for example, as 3474496 + 506944 = 1864^2 + 712^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (3981449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2471 + ... + 3750.

Almost surely, 2^3981440 is an apocalyptic number.

It is an amenable number.

3981440 is an abundant number, since it is smaller than the sum of its proper divisors (5538220).

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

3981440 is an equidigital number, since it uses as much as digits as its factorization.

3981440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6240 (or 6228 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 3981440 is about 1995.3546050765. The cubic root of 3981440 is about 158.4942064510.

The spelling of 3981440 in words is "three million, nine hundred eighty-one thousand, four hundred forty".