3978123840 has 196 divisors, whose sum is σ = 14203696764. Its totient is φ = 1060770816.

The previous prime is 3978123839. The next prime is 3978123859. The reversal of 3978123840 is 483218793.

It can be written as a sum of positive squares in 2 ways, for example, as 1445216256 + 2532907584 = 38016^2 + 50328^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 224754 + ... + 241806.

Almost surely, 2^3978123840 is an apocalyptic number.

3978123840 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 3978123840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7101848382).

3978123840 is an abundant number, since it is smaller than the sum of its proper divisors (10225572924).

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

3978123840 is an equidigital number, since it uses as much as digits as its factorization.

3978123840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17088 (or 17063 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 3978123840 is about 63072.3698619292. The cubic root of 3978123840 is about 1584.5019070644.

The spelling of 3978123840 in words is "three billion, nine hundred seventy-eight million, one hundred twenty-three thousand, eight hundred forty".