19678816879 has 4 divisors (see below), whose sum is σ = 19681644384. Its totient is φ = 19675989376.

The previous prime is 19678816841. The next prime is 19678816901. The reversal of 19678816879 is 97861887691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97861887691 = 269 ⋅363798839.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19678816879 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 (19678816279) 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, 1403287 + ... + 1417240.

It is an arithmetic number, because the mean of its divisors is an integer number (4920411096).

Almost surely, 2^19678816879 is an apocalyptic number.

19678816879 is a deficient number, since it is larger than the sum of its proper divisors (2827505).

19678816879 is an equidigital number, since it uses as much as digits as its factorization.

19678816879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2827504.

The product of its digits is 73156608, while the sum is 70.

The spelling of 19678816879 in words is "nineteen billion, six hundred seventy-eight million, eight hundred sixteen thousand, eight hundred seventy-nine".