3981400128 has 140 divisors (see below), whose sum is σ = 11829147792. Its totient is φ = 1324097280.

The previous prime is 3981400099. The next prime is 3981400151. The reversal of 3981400128 is 8210041893.

3981400128 is a `hidden beast` number, since 398 + 140 + 0 + 128 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 3981400092 and 3981400101.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4203751 + ... + 4204697.

Almost surely, 2^3981400128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3981400128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5914573896).

3981400128 is an abundant number, since it is smaller than the sum of its proper divisors (7847747664).

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

3981400128 is an equidigital number, since it uses as much as digits as its factorization.

3981400128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1782 (or 1763 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 3981400128 is about 63098.3369669915. The cubic root of 3981400128 is about 1584.9367737088.

The spelling of 3981400128 in words is "three billion, nine hundred eighty-one million, four hundred thousand, one hundred twenty-eight".