18420213 has 16 divisors (see below), whose sum is σ = 28546560. Its totient is φ = 10346736.

The previous prime is 18420209. The next prime is 18420221. The reversal of 18420213 is 31202481.

It is not a de Polignac number, because 18420213 - 2² = 18420209 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 18420213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18422213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6195 + ... + 8672.

It is an arithmetic number, because the mean of its divisors is an integer number (1784160).

Almost surely, 2^18420213 is an apocalyptic number.

It is an amenable number.

18420213 is a deficient number, since it is larger than the sum of its proper divisors (10126347).

18420213 is a wasteful number, since it uses less digits than its factorization.

18420213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14936.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 18420213 is about 4291.8775611613. The cubic root of 18420213 is about 264.0978602998.

Adding to 18420213 its reverse (31202481), we get a palindrome (49622694).

The spelling of 18420213 in words is "eighteen million, four hundred twenty thousand, two hundred thirteen".