21194213 has 2 divisors, whose sum is σ = 21194214. Its totient is φ = 21194212.

The previous prime is 21194203. The next prime is 21194219. The reversal of 21194213 is 31249112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12061729 + 9132484 = 3473^2 + 3022^2 .

It is a cyclic number.

It is not a de Polignac number, because 21194213 - 2⁴ = 21194197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21194219) 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, 10597106 + 10597107.

It is an arithmetic number, because the mean of its divisors is an integer number (10597107).

Almost surely, 2^21194213 is an apocalyptic number.

It is an amenable number.

21194213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21194213 is an equidigital number, since it uses as much as digits as its factorization.

21194213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 23.

The square root of 21194213 is about 4603.7173023547. The cubic root of 21194213 is about 276.7403153876.

The spelling of 21194213 in words is "twenty-one million, one hundred ninety-four thousand, two hundred thirteen".