3981990 has 64 divisors (see below), whose sum is σ = 10368000. Its totient is φ = 975744.

The previous prime is 3981973. The next prime is 3982031. The reversal of 3981990 is 991893.

3981990 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19911 + ... + 20109.

It is an arithmetic number, because the mean of its divisors is an integer number (162000).

Almost surely, 2^3981990 is an apocalyptic number.

3981990 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 3981990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5184000).

3981990 is an abundant number, since it is smaller than the sum of its proper divisors (6386010).

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

3981990 is a wasteful number, since it uses less digits than its factorization.

3981990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261.

The product of its (nonzero) digits is 17496, while the sum is 39.

The square root of 3981990 is about 1995.4924204316. The cubic root of 3981990 is about 158.5015042963.

The spelling of 3981990 in words is "three million, nine hundred eighty-one thousand, nine hundred ninety".