18506813 has 8 divisors (see below), whose sum is σ = 20394528. Its totient is φ = 16685424.

The previous prime is 18506791. The next prime is 18506833. The reversal of 18506813 is 31860581.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18506813 - 2¹⁰ = 18505789 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 18506813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18506833) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15995 + ... + 17112.

It is an arithmetic number, because the mean of its divisors is an integer number (2549316).

Almost surely, 2^18506813 is an apocalyptic number.

18506813 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

18506813 is a deficient number, since it is larger than the sum of its proper divisors (1887715).

18506813 is a wasteful number, since it uses less digits than its factorization.

18506813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33163.

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 18506813 is about 4301.9545557804. The cubic root of 18506813 is about 264.5110861881.

The spelling of 18506813 in words is "eighteen million, five hundred six thousand, eight hundred thirteen".