18011947 has 4 divisors (see below), whose sum is σ = 18258760. Its totient is φ = 17765136.

The previous prime is 18011941. The next prime is 18011977. The reversal of 18011947 is 74911081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74911081 = 7 ⋅10701583.

It is a cyclic number.

It is not a de Polignac number, because 18011947 - 2¹⁵ = 17979179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18011941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123297 + ... + 123442.

It is an arithmetic number, because the mean of its divisors is an integer number (4564690).

Almost surely, 2^18011947 is an apocalyptic number.

18011947 is a deficient number, since it is larger than the sum of its proper divisors (246813).

18011947 is an equidigital number, since it uses as much as digits as its factorization.

18011947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246812.

The product of its (nonzero) digits is 2016, while the sum is 31.

The square root of 18011947 is about 4244.0484210244. The cubic root of 18011947 is about 262.1321080745.

The spelling of 18011947 in words is "eighteen million, eleven thousand, nine hundred forty-seven".