18208213 has 4 divisors (see below), whose sum is σ = 19166560. Its totient is φ = 17249868.

The previous prime is 18208189. The next prime is 18208231. The reversal of 18208213 is 31280281.

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.

It is a cyclic number.

It is not a de Polignac number, because 18208213 - 2¹⁷ = 18077141 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 (18208013) 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, 479145 + ... + 479182.

It is an arithmetic number, because the mean of its divisors is an integer number (4791640).

Almost surely, 2^18208213 is an apocalyptic number.

It is an amenable number.

18208213 is a deficient number, since it is larger than the sum of its proper divisors (958347).

18208213 is an equidigital number, since it uses as much as digits as its factorization.

18208213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958346.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 18208213 is about 4267.1082714175. The cubic root of 18208213 is about 263.0807724650.

Adding to 18208213 its reverse (31280281), we get a palindrome (49488494).

The spelling of 18208213 in words is "eighteen million, two hundred eight thousand, two hundred thirteen".