22190821 has 2 divisors, whose sum is σ = 22190822. Its totient is φ = 22190820.

The previous prime is 22190813. The next prime is 22190893. The reversal of 22190821 is 12809122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14737921 + 7452900 = 3839^2 + 2730^2 .

It is a cyclic number.

It is not a de Polignac number, because 22190821 - 2³ = 22190813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22190801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11095410 + 11095411.

It is an arithmetic number, because the mean of its divisors is an integer number (11095411).

Almost surely, 2^22190821 is an apocalyptic number.

It is an amenable number.

22190821 is a deficient number, since it is larger than the sum of its proper divisors (1).

22190821 is an equidigital number, since it uses as much as digits as its factorization.

22190821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 22190821 is about 4710.7134279215. The cubic root of 22190821 is about 281.0117352613.

Adding to 22190821 its reverse (12809122), we get a palindrome (34999943).

The spelling of 22190821 in words is "twenty-two million, one hundred ninety thousand, eight hundred twenty-one".