18500213 has 4 divisors (see below), whose sum is σ = 18641568. Its totient is φ = 18358860.

The previous prime is 18500203. The next prime is 18500219. The reversal of 18500213 is 31200581.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31200581 = 23 ⋅1356547.

It is a cyclic number.

It is not a de Polignac number, because 18500213 - 2¹⁸ = 18238069 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 (18500219) 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, 70481 + ... + 70742.

It is an arithmetic number, because the mean of its divisors is an integer number (4660392).

Almost surely, 2^18500213 is an apocalyptic number.

It is an amenable number.

18500213 is a deficient number, since it is larger than the sum of its proper divisors (141355).

18500213 is a wasteful number, since it uses less digits than its factorization.

18500213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141354.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 18500213 is about 4301.1873941971. The cubic root of 18500213 is about 264.4796386569.

Adding to 18500213 its reverse (31200581), we get a palindrome (49700794).

The spelling of 18500213 in words is "eighteen million, five hundred thousand, two hundred thirteen".