3978194615999 has 4 divisors (see below), whose sum is σ = 4000173591960. Its totient is φ = 3956215640040.

The previous prime is 3978194615971. The next prime is 3978194616031. The reversal of 3978194615999 is 9995164918793.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 3978194615999 - 2²⁴ = 3978177838783 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3978194615299) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10989487709 + ... + 10989488070.

It is an arithmetic number, because the mean of its divisors is an integer number (1000043397990).

Almost surely, 2^{3978194615999} is an apocalyptic number.

3978194615999 is a deficient number, since it is larger than the sum of its proper divisors (21978975961).

3978194615999 is a wasteful number, since it uses less digits than its factorization.

3978194615999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21978975960.

The product of its digits is 1190427840, while the sum is 80.

The spelling of 3978194615999 in words is "three trillion, nine hundred seventy-eight billion, one hundred ninety-four million, six hundred fifteen thousand, nine hundred ninety-nine".