21752243 has 2 divisors, whose sum is σ = 21752244. Its totient is φ = 21752242.

The previous prime is 21752239. The next prime is 21752267. The reversal of 21752243 is 34225712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21752243 - 2² = 21752239 is a prime.

It is not a weakly prime, because it can be changed into another prime (21752293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10876121 + 10876122.

It is an arithmetic number, because the mean of its divisors is an integer number (10876122).

Almost surely, 2^21752243 is an apocalyptic number.

21752243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21752243 is an equidigital number, since it uses as much as digits as its factorization.

21752243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3360, while the sum is 26.

The square root of 21752243 is about 4663.9299951865. The cubic root of 21752243 is about 279.1481037730.

Adding to 21752243 its reverse (34225712), we get a palindrome (55977955).

The spelling of 21752243 in words is "twenty-one million, seven hundred fifty-two thousand, two hundred forty-three".