18105821047 has 4 divisors (see below), whose sum is σ = 18107008920. Its totient is φ = 18104633176.

The previous prime is 18105821029. The next prime is 18105821059. The reversal of 18105821047 is 74012850181.

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 18105821047 - 2⁷ = 18105820919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18105820997 and 18105821015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18105821017) 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, 570772 + ... + 601657.

It is an arithmetic number, because the mean of its divisors is an integer number (4526752230).

Almost surely, 2^18105821047 is an apocalyptic number.

18105821047 is a deficient number, since it is larger than the sum of its proper divisors (1187873).

18105821047 is a wasteful number, since it uses less digits than its factorization.

18105821047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1187872.

The product of its (nonzero) digits is 17920, while the sum is 37.

The spelling of 18105821047 in words is "eighteen billion, one hundred five million, eight hundred twenty-one thousand, forty-seven".