19215978685 has 16 divisors (see below), whose sum is σ = 23224365360. Its totient is φ = 15263050240.

The previous prime is 19215978671. The next prime is 19215978701. The reversal of 19215978685 is 58687951291.

It can be written as a sum of positive squares in 8 ways, for example, as 1159606809 + 18056371876 = 34053^2 + 134374^2 .

It is not a de Polignac number, because 19215978685 - 2⁵ = 19215978653 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 369705 + ... + 418465.

It is an arithmetic number, because the mean of its divisors is an integer number (1451522835).

Almost surely, 2^19215978685 is an apocalyptic number.

It is an amenable number.

19215978685 is a deficient number, since it is larger than the sum of its proper divisors (4008386675).

19215978685 is a wasteful number, since it uses less digits than its factorization.

19215978685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49328.

The product of its digits is 10886400, while the sum is 61.

The spelling of 19215978685 in words is "nineteen billion, two hundred fifteen million, nine hundred seventy-eight thousand, six hundred eighty-five".