3978391840 has 48 divisors (see below), whose sum is σ = 9473006592. Its totient is φ = 1578818304.

The previous prime is 3978391801. The next prime is 3978391843. The reversal of 3978391840 is 481938793.

It is not an unprimeable number, because it can be changed into a prime (3978391843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77574 + ... + 118213.

It is an arithmetic number, because the mean of its divisors is an integer number (197354304).

Almost surely, 2^3978391840 is an apocalyptic number.

It is an amenable number.

3978391840 is an abundant number, since it is smaller than the sum of its proper divisors (5494614752).

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

3978391840 is a wasteful number, since it uses less digits than its factorization.

3978391840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195929 (or 195921 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 52.

The square root of 3978391840 is about 63074.4943697530. The cubic root of 3978391840 is about 1584.5374880730.

The spelling of 3978391840 in words is "three billion, nine hundred seventy-eight million, three hundred ninety-one thousand, eight hundred forty".