21722221061 has 4 divisors (see below), whose sum is σ = 21783757452. Its totient is φ = 21660684672.

The previous prime is 21722221057. The next prime is 21722221069. The reversal of 21722221061 is 16012222712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17272530625 + 4449690436 = 131425^2 + 66706^2 .

It is a cyclic number.

It is not a de Polignac number, because 21722221061 - 2² = 21722221057 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21722221061.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722221069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30767666 + ... + 30768371.

It is an arithmetic number, because the mean of its divisors is an integer number (5445939363).

Almost surely, 2^21722221061 is an apocalyptic number.

It is an amenable number.

21722221061 is a deficient number, since it is larger than the sum of its proper divisors (61536391).

21722221061 is an equidigital number, since it uses as much as digits as its factorization.

21722221061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61536390.

The product of its (nonzero) digits is 1344, while the sum is 26.

Adding to 21722221061 its reverse (16012222712), we get a palindrome (37734443773).

The spelling of 21722221061 in words is "twenty-one billion, seven hundred twenty-two million, two hundred twenty-one thousand, sixty-one".