19781318985 has 16 divisors (see below), whose sum is σ = 31891717440. Its totient is φ = 10469501120.

The previous prime is 19781318941. The next prime is 19781319031. The reversal of 19781318985 is 58981318791.

It is a happy number.

It is not a de Polignac number, because 19781318985 - 2⁸ = 19781318729 is a prime.

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, 5031450 + ... + 5035379.

It is an arithmetic number, because the mean of its divisors is an integer number (1993232340).

Almost surely, 2^19781318985 is an apocalyptic number.

19781318985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19781318985 is a deficient number, since it is larger than the sum of its proper divisors (12110398455).

19781318985 is a wasteful number, since it uses less digits than its factorization.

19781318985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10066968.

The product of its digits is 4354560, while the sum is 60.

The spelling of 19781318985 in words is "nineteen billion, seven hundred eighty-one million, three hundred eighteen thousand, nine hundred eighty-five".