21222739 has 2 divisors, whose sum is σ = 21222740. Its totient is φ = 21222738.

The previous prime is 21222697. The next prime is 21222743. The reversal of 21222739 is 93722212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21222739 - 2⁷ = 21222611 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21223739) 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, 10611369 + 10611370.

It is an arithmetic number, because the mean of its divisors is an integer number (10611370).

Almost surely, 2^21222739 is an apocalyptic number.

21222739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222739 is an equidigital number, since it uses as much as digits as its factorization.

21222739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 28.

The square root of 21222739 is about 4606.8144091118. The cubic root of 21222739 is about 276.8644177412.

The spelling of 21222739 in words is "twenty-one million, two hundred twenty-two thousand, seven hundred thirty-nine".