18917047 has 4 divisors (see below), whose sum is σ = 18925776. Its totient is φ = 18908320.

The previous prime is 18917029. The next prime is 18917053. The reversal of 18917047 is 74071981.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 74071981 = 4423 ⋅16747.

It is a cyclic number.

It is not a de Polignac number, because 18917047 - 2²³ = 10528439 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18916997 and 18917015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18917057) 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, 1647 + ... + 6367.

It is an arithmetic number, because the mean of its divisors is an integer number (4731444).

Almost surely, 2^18917047 is an apocalyptic number.

18917047 is a deficient number, since it is larger than the sum of its proper divisors (8729).

18917047 is an equidigital number, since it uses as much as digits as its factorization.

18917047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8728.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 18917047 is about 4349.3731732285. The cubic root of 18917047 is about 266.4512616397.

The spelling of 18917047 in words is "eighteen million, nine hundred seventeen thousand, forty-seven".