22000721 has 2 divisors, whose sum is σ = 22000722. Its totient is φ = 22000720.

The previous prime is 22000679. The next prime is 22000753. The reversal of 22000721 is 12700022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20151121 + 1849600 = 4489^2 + 1360^2 .

It is a cyclic number.

It is not a de Polignac number, because 22000721 - 2²² = 17806417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 22000696 and 22000705.

It is not a weakly prime, because it can be changed into another prime (22000021) 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, 11000360 + 11000361.

It is an arithmetic number, because the mean of its divisors is an integer number (11000361).

Almost surely, 2^22000721 is an apocalyptic number.

It is an amenable number.

22000721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22000721 is an equidigital number, since it uses as much as digits as its factorization.

22000721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56, while the sum is 14.

The square root of 22000721 is about 4690.4926180520. The cubic root of 22000721 is about 280.2069940478.

Adding to 22000721 its reverse (12700022), we get a palindrome (34700743).

The spelling of 22000721 in words is "twenty-two million, seven hundred twenty-one", and thus it is an aban number.