21750229 has 2 divisors, whose sum is σ = 21750230. Its totient is φ = 21750228.

The previous prime is 21750181. The next prime is 21750241. The reversal of 21750229 is 92205712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19158129 + 2592100 = 4377^2 + 1610^2 .

It is a cyclic number.

It is not a de Polignac number, because 21750229 - 2⁷ = 21750101 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21750197 and 21750206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21750329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10875114 + 10875115.

It is an arithmetic number, because the mean of its divisors is an integer number (10875115).

Almost surely, 2^21750229 is an apocalyptic number.

It is an amenable number.

21750229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21750229 is an equidigital number, since it uses as much as digits as its factorization.

21750229 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21750229 is about 4663.7140778568. The cubic root of 21750229 is about 279.1394882380.

The spelling of 21750229 in words is "twenty-one million, seven hundred fifty thousand, two hundred twenty-nine".