18506819 has 4 divisors (see below), whose sum is σ = 18523896. Its totient is φ = 18489744.

The previous prime is 18506791. The next prime is 18506833. The reversal of 18506819 is 91860581.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18506819 is a prime.

It is a super-2 number, since 2×18506819² = 685004698997522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18506849) 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, 6794 + ... + 9119.

It is an arithmetic number, because the mean of its divisors is an integer number (4630974).

Almost surely, 2^18506819 is an apocalyptic number.

18506819 is a deficient number, since it is larger than the sum of its proper divisors (17077).

18506819 is a wasteful number, since it uses less digits than its factorization.

18506819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17076.

The product of its (nonzero) digits is 17280, while the sum is 38.

The square root of 18506819 is about 4301.9552531378. The cubic root of 18506819 is about 264.5111147734.

The spelling of 18506819 in words is "eighteen million, five hundred six thousand, eight hundred nineteen".