21842573 has 2 divisors, whose sum is σ = 21842574. Its totient is φ = 21842572.

The previous prime is 21842551. The next prime is 21842591. The reversal of 21842573 is 37524812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19731364 + 2111209 = 4442^2 + 1453^2 .

It is a cyclic number.

It is not a de Polignac number, because 21842573 - 2¹⁶ = 21777037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21842593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10921286 + 10921287.

It is an arithmetic number, because the mean of its divisors is an integer number (10921287).

Almost surely, 2^21842573 is an apocalyptic number.

It is an amenable number.

21842573 is a deficient number, since it is larger than the sum of its proper divisors (1).

21842573 is an equidigital number, since it uses as much as digits as its factorization.

21842573 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 32.

The square root of 21842573 is about 4673.6038556985. The cubic root of 21842573 is about 279.5339739361.

The spelling of 21842573 in words is "twenty-one million, eight hundred forty-two thousand, five hundred seventy-three".