18419221 has 2 divisors, whose sum is σ = 18419222. Its totient is φ = 18419220.

The previous prime is 18419207. The next prime is 18419243. The reversal of 18419221 is 12291481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13950225 + 4468996 = 3735^2 + 2114^2 .

It is a cyclic number.

It is not a de Polignac number, because 18419221 - 2⁹ = 18418709 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18419221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18419201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9209610 + 9209611.

It is an arithmetic number, because the mean of its divisors is an integer number (9209611).

Almost surely, 2^18419221 is an apocalyptic number.

It is an amenable number.

18419221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18419221 is an equidigital number, since it uses as much as digits as its factorization.

18419221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 28.

The square root of 18419221 is about 4291.7619924688. The cubic root of 18419221 is about 264.0931193163.

The spelling of 18419221 in words is "eighteen million, four hundred nineteen thousand, two hundred twenty-one".