18429056221 has 2 divisors, whose sum is σ = 18429056222. Its totient is φ = 18429056220.

The previous prime is 18429056207. The next prime is 18429056281. The reversal of 18429056221 is 12265092481.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18208533721 + 220522500 = 134939^2 + 14850^2 .

It is an emirp because it is prime and its reverse (12265092481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18429056221 - 2²³ = 18420667613 is a prime.

It is a super-2 number, since 2×18429056221² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18429056281) 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 as a sum of consecutive naturals, namely, 9214528110 + 9214528111.

It is an arithmetic number, because the mean of its divisors is an integer number (9214528111).

Almost surely, 2^18429056221 is an apocalyptic number.

It is an amenable number.

18429056221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18429056221 is an equidigital number, since it uses as much as digits as its factorization.

18429056221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69120, while the sum is 40.

The spelling of 18429056221 in words is "eighteen billion, four hundred twenty-nine million, fifty-six thousand, two hundred twenty-one".