21222765647 has 2 divisors, whose sum is σ = 21222765648. Its totient is φ = 21222765646.

The previous prime is 21222765617. The next prime is 21222765691. The reversal of 21222765647 is 74656722212.

It is an a-pointer prime, because the next prime (21222765691) can be obtained adding 21222765647 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21222765647 - 2¹⁴ = 21222749263 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21222765598 and 21222765607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222765617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611382823 + 10611382824.

It is an arithmetic number, because the mean of its divisors is an integer number (10611382824).

Almost surely, 2^21222765647 is an apocalyptic number.

21222765647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222765647 is an equidigital number, since it uses as much as digits as its factorization.

21222765647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 564480, while the sum is 44.

The spelling of 21222765647 in words is "twenty-one billion, two hundred twenty-two million, seven hundred sixty-five thousand, six hundred forty-seven".