22731721 has 2 divisors, whose sum is σ = 22731722. Its totient is φ = 22731720.

The previous prime is 22731719. The next prime is 22731743. The reversal of 22731721 is 12713722.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21855625 + 876096 = 4675^2 + 936^2 .

It is a cyclic number.

It is not a de Polignac number, because 22731721 - 2¹ = 22731719 is a prime.

It is a super-2 number, since 2×22731721² = 1033462279243682, which contains 22 as substring.

Together with 22731719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (22731781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11365860 + 11365861.

It is an arithmetic number, because the mean of its divisors is an integer number (11365861).

Almost surely, 2^22731721 is an apocalyptic number.

It is an amenable number.

22731721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22731721 is an equidigital number, since it uses as much as digits as its factorization.

22731721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1176, while the sum is 25.

The square root of 22731721 is about 4767.7794621815. The cubic root of 22731721 is about 283.2766464063.

The spelling of 22731721 in words is "twenty-two million, seven hundred thirty-one thousand, seven hundred twenty-one".