19853615816 has 8 divisors (see below), whose sum is σ = 37225529670. Its totient is φ = 9926807904.

The previous prime is 19853615791. The next prime is 19853615843. The reversal of 19853615816 is 61851635891.

It can be written as a sum of positive squares in only one way, i.e., 10030823716 + 9822792100 = 100154^2 + 99110^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1240850981 + ... + 1240850996.

Almost surely, 2^19853615816 is an apocalyptic number.

It is an amenable number.

19853615816 is a deficient number, since it is larger than the sum of its proper divisors (17371913854).

19853615816 is a wasteful number, since it uses less digits than its factorization.

19853615816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2481701983 (or 2481701979 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 53.

The spelling of 19853615816 in words is "nineteen billion, eight hundred fifty-three million, six hundred fifteen thousand, eight hundred sixteen".