21252223 has 2 divisors, whose sum is σ = 21252224. Its totient is φ = 21252222.

The previous prime is 21252211. The next prime is 21252239. The reversal of 21252223 is 32225212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21252223 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21252223.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21252293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626111 + 10626112.

It is an arithmetic number, because the mean of its divisors is an integer number (10626112).

Almost surely, 2^21252223 is an apocalyptic number.

21252223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252223 is an equidigital number, since it uses as much as digits as its factorization.

21252223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 19.

The square root of 21252223 is about 4610.0133405447. The cubic root of 21252223 is about 276.9925710580.

Adding to 21252223 its reverse (32225212), we get a palindrome (53477435).

The spelling of 21252223 in words is "twenty-one million, two hundred fifty-two thousand, two hundred twenty-three".