21222018016817 has 2 divisors, whose sum is σ = 21222018016818. Its totient is φ = 21222018016816.

The previous prime is 21222018016807. The next prime is 21222018016879. The reversal of 21222018016817 is 71861081022212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15685013705761 + 5537004311056 = 3960431^2 + 2353084^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222018016817 - 2²⁴ = 21222001239601 is a prime.

It is a super-2 number, since 2×21222018016817² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21222018016807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611009008408 + 10611009008409.

It is an arithmetic number, because the mean of its divisors is an integer number (10611009008409).

Almost surely, 2^{21222018016817} is an apocalyptic number.

It is an amenable number.

21222018016817 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222018016817 is an equidigital number, since it uses as much as digits as its factorization.

21222018016817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43008, while the sum is 41.

The spelling of 21222018016817 in words is "twenty-one trillion, two hundred twenty-two billion, eighteen million, sixteen thousand, eight hundred seventeen".