21222765643 has 16 divisors (see below), whose sum is σ = 23588651520. Its totient is φ = 18991451776.

The previous prime is 21222765617. The next prime is 21222765647. The reversal of 21222765643 is 34656722212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21222765643 - 2⁵ = 21222765611 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222765596 and 21222765605.

It is not an unprimeable number, because it can be changed into a prime (21222765647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 97213 + ... + 227806.

It is an arithmetic number, because the mean of its divisors is an integer number (1474290720).

Almost surely, 2^21222765643 is an apocalyptic number.

21222765643 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21222765643 is a deficient number, since it is larger than the sum of its proper divisors (2365885877).

21222765643 is a wasteful number, since it uses less digits than its factorization.

21222765643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325226.

The product of its digits is 241920, while the sum is 40.

The spelling of 21222765643 in words is "twenty-one billion, two hundred twenty-two million, seven hundred sixty-five thousand, six hundred forty-three".