21799243 has 2 divisors, whose sum is σ = 21799244. Its totient is φ = 21799242.

The previous prime is 21799241. The next prime is 21799279. The reversal of 21799243 is 34299712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21799243 - 2¹ = 21799241 is a prime.

Together with 21799241, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21799241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10899621 + 10899622.

It is an arithmetic number, because the mean of its divisors is an integer number (10899622).

Almost surely, 2^21799243 is an apocalyptic number.

21799243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21799243 is an equidigital number, since it uses as much as digits as its factorization.

21799243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 37.

The square root of 21799243 is about 4668.9659454744. The cubic root of 21799243 is about 279.3490106065.

The spelling of 21799243 in words is "twenty-one million, seven hundred ninety-nine thousand, two hundred forty-three".