22047721 has 2 divisors, whose sum is σ = 22047722. Its totient is φ = 22047720.

The previous prime is 22047719. The next prime is 22047797. The reversal of 22047721 is 12774022.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17472400 + 4575321 = 4180^2 + 2139^2 .

It is a cyclic number.

It is not a de Polignac number, because 22047721 - 2¹ = 22047719 is a prime.

It is a super-2 number, since 2×22047721² = 972204002587682, which contains 22 as substring.

Together with 22047719, it forms a pair of twin primes.

It is the 4696-th Hogben number.

It is not a weakly prime, because it can be changed into another prime (22047121) by changing a digit.

It is a nontrivial repunit in base 4695.

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, 11023860 + 11023861.

It is an arithmetic number, because the mean of its divisors is an integer number (11023861).

Almost surely, 2^22047721 is an apocalyptic number.

It is an amenable number.

22047721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22047721 is an equidigital number, since it uses as much as digits as its factorization.

22047721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1568, while the sum is 25.

The square root of 22047721 is about 4695.5000798637. The cubic root of 22047721 is about 280.4063869328.

The spelling of 22047721 in words is "twenty-two million, forty-seven thousand, seven hundred twenty-one".