19783978685 has 8 divisors (see below), whose sum is σ = 23747973216. Its totient is φ = 15822383760.

The previous prime is 19783978663. The next prime is 19783978723. The reversal of 19783978685 is 58687938791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-19783978685 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 581711 + ... + 614780.

It is an arithmetic number, because the mean of its divisors is an integer number (2968496652).

Almost surely, 2^19783978685 is an apocalyptic number.

It is an amenable number.

19783978685 is a deficient number, since it is larger than the sum of its proper divisors (3963994531).

19783978685 is a wasteful number, since it uses less digits than its factorization.

19783978685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1199803.

The product of its digits is 182891520, while the sum is 71.

The spelling of 19783978685 in words is "nineteen billion, seven hundred eighty-three million, nine hundred seventy-eight thousand, six hundred eighty-five".