19811775047 has 4 divisors (see below), whose sum is σ = 19812331416. Its totient is φ = 19811218680.

The previous prime is 19811775041. The next prime is 19811775119. The reversal of 19811775047 is 74057711891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19811775047 - 2⁴ = 19811775031 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19811774986 and 19811775004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19811775041) 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, 220829 + ... + 297302.

It is an arithmetic number, because the mean of its divisors is an integer number (4953082854).

Almost surely, 2^19811775047 is an apocalyptic number.

19811775047 is a deficient number, since it is larger than the sum of its proper divisors (556369).

19811775047 is an equidigital number, since it uses as much as digits as its factorization.

19811775047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556368.

The product of its (nonzero) digits is 493920, while the sum is 50.

The spelling of 19811775047 in words is "nineteen billion, eight hundred eleven million, seven hundred seventy-five thousand, forty-seven".