21216042056329 has 2 divisors, whose sum is σ = 21216042056330. Its totient is φ = 21216042056328.

The previous prime is 21216042056323. The next prime is 21216042056369. The reversal of 21216042056329 is 92365024061212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19283866995600 + 1932175060729 = 4391340^2 + 1390027^2 .

It is a cyclic number.

It is not a de Polignac number, because 21216042056329 - 2¹⁷ = 21216041925257 is a prime.

It is not a weakly prime, because it can be changed into another prime (21216042056323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608021028164 + 10608021028165.

It is an arithmetic number, because the mean of its divisors is an integer number (10608021028165).

Almost surely, 2^{21216042056329} is an apocalyptic number.

It is an amenable number.

21216042056329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216042056329 is an equidigital number, since it uses as much as digits as its factorization.

21216042056329 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 43.

The spelling of 21216042056329 in words is "twenty-one trillion, two hundred sixteen billion, forty-two million, fifty-six thousand, three hundred twenty-nine".