3987840 has 128 divisors (see below), whose sum is σ = 13317120. Its totient is φ = 1013760.

The previous prime is 3987839. The next prime is 3987847. The reversal of 3987840 is 487893.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3987847) 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, 59487 + ... + 59553.

It is an arithmetic number, because the mean of its divisors is an integer number (104040).

Almost surely, 2^3987840 is an apocalyptic number.

3987840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3987840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6658560).

3987840 is an abundant number, since it is smaller than the sum of its proper divisors (9329280).

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

3987840 is a wasteful number, since it uses less digits than its factorization.

3987840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 3987840 is about 1996.9576860815. The cubic root of 3987840 is about 158.5790852796.

The spelling of 3987840 in words is "three million, nine hundred eighty-seven thousand, eight hundred forty".