18261947 has 4 divisors (see below), whose sum is σ = 19922136. Its totient is φ = 16601760.

The previous prime is 18261937. The next prime is 18261949. The reversal of 18261947 is 74916281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74916281 = 11 ⋅6810571.

It is a cyclic number.

It is not a de Polignac number, because 18261947 - 2¹⁸ = 17999803 is a prime.

It is a pancake number, because a pancake can be divided into 18261947 parts by 6043 straight cuts.

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 18261947.

It is not an unprimeable number, because it can be changed into a prime (18261949) 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, 830078 + ... + 830099.

It is an arithmetic number, because the mean of its divisors is an integer number (4980534).

Almost surely, 2^18261947 is an apocalyptic number.

18261947 is a deficient number, since it is larger than the sum of its proper divisors (1660189).

18261947 is a wasteful number, since it uses less digits than its factorization.

18261947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1660188.

The product of its digits is 24192, while the sum is 38.

The square root of 18261947 is about 4273.3999344784. The cubic root of 18261947 is about 263.3393096260.

It can be divided in two parts, 1826 and 1947, that added together give a palindrome (3773).

The spelling of 18261947 in words is "eighteen million, two hundred sixty-one thousand, nine hundred forty-seven".