18516487 has 4 divisors (see below), whose sum is σ = 20199816. Its totient is φ = 16833160.

The previous prime is 18516479. The next prime is 18516499. The reversal of 18516487 is 78461581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78461581 = 11 ⋅7132871.

It is a cyclic number.

It is not a de Polignac number, because 18516487 - 2³ = 18516479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18516437) 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, 841648 + ... + 841669.

It is an arithmetic number, because the mean of its divisors is an integer number (5049954).

Almost surely, 2^18516487 is an apocalyptic number.

18516487 is a deficient number, since it is larger than the sum of its proper divisors (1683329).

18516487 is a wasteful number, since it uses less digits than its factorization.

18516487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1683328.

The product of its digits is 53760, while the sum is 40.

The square root of 18516487 is about 4303.0787815238. The cubic root of 18516487 is about 264.5571671370.

It can be divided in two parts, 1851 and 6487, that added together give a palindrome (8338).

The spelling of 18516487 in words is "eighteen million, five hundred sixteen thousand, four hundred eighty-seven".