18639047 has 4 divisors (see below), whose sum is σ = 21301776. Its totient is φ = 15976320.

The previous prime is 18639013. The next prime is 18639059. The reversal of 18639047 is 74093681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74093681 = 619 ⋅119699.

It is a cyclic number.

It is not a de Polignac number, because 18639047 - 2¹⁸ = 18376903 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18639047.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18639067) 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, 1331354 + ... + 1331367.

It is an arithmetic number, because the mean of its divisors is an integer number (5325444).

Almost surely, 2^18639047 is an apocalyptic number.

18639047 is a deficient number, since it is larger than the sum of its proper divisors (2662729).

18639047 is an equidigital number, since it uses as much as digits as its factorization.

18639047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2662728.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 18639047 is about 4317.2962603926. The cubic root of 18639047 is about 265.1395823335.

The spelling of 18639047 in words is "eighteen million, six hundred thirty-nine thousand, forty-seven".