22320721 has 2 divisors, whose sum is σ = 22320722. Its totient is φ = 22320720.

The previous prime is 22320709. The next prime is 22320737. The reversal of 22320721 is 12702322.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20250000 + 2070721 = 4500^2 + 1439^2 .

It is a cyclic number.

It is not a de Polignac number, because 22320721 - 2⁵ = 22320689 is a prime.

It is a super-3 number, since 3×22320721³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (22320751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11160360 + 11160361.

It is an arithmetic number, because the mean of its divisors is an integer number (11160361).

Almost surely, 2^22320721 is an apocalyptic number.

It is an amenable number.

22320721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22320721 is an equidigital number, since it uses as much as digits as its factorization.

22320721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 22320721 is about 4724.4810297005. The cubic root of 22320721 is about 281.5589949831.

The spelling of 22320721 in words is "twenty-two million, three hundred twenty thousand, seven hundred twenty-one".