3978719778 has 16 divisors (see below), whose sum is σ = 8680843296. Its totient is φ = 1205672640.

The previous prime is 3978719753. The next prime is 3978719783. The reversal of 3978719778 is 8779178793.

It is a happy number.

It is a super-2 number, since 2×3978719778² = 31660422143696738568, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (66), and also a Moran number because the ratio is a prime number: 60283633 = 3978719778 / (3 + 9 + 7 + 8 + 7 + 1 + 9 + 7 + 7 + 8).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30141751 + ... + 30141882.

It is an arithmetic number, because the mean of its divisors is an integer number (542552706).

Almost surely, 2^3978719778 is an apocalyptic number.

3978719778 is an abundant number, since it is smaller than the sum of its proper divisors (4702123518).

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

3978719778 is a wasteful number, since it uses less digits than its factorization.

3978719778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60283649.

The product of its digits is 37340352, while the sum is 66.

The square root of 3978719778 is about 63077.0939248155. The cubic root of 3978719778 is about 1584.5810245737.

The spelling of 3978719778 in words is "three billion, nine hundred seventy-eight million, seven hundred nineteen thousand, seven hundred seventy-eight".