21582191 has 2 divisors, whose sum is σ = 21582192. Its totient is φ = 21582190.

The previous prime is 21582181. The next prime is 21582199. The reversal of 21582191 is 19128512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21582191 - 2¹⁰ = 21581167 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21582199) 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, 10791095 + 10791096.

It is an arithmetic number, because the mean of its divisors is an integer number (10791096).

Almost surely, 2^21582191 is an apocalyptic number.

21582191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21582191 is an equidigital number, since it uses as much as digits as its factorization.

21582191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 29.

The square root of 21582191 is about 4645.6636770218. The cubic root of 21582191 is about 278.4187700316.

The spelling of 21582191 in words is "twenty-one million, five hundred eighty-two thousand, one hundred ninety-one".