21216556021301 has 2 divisors, whose sum is σ = 21216556021302. Its totient is φ = 21216556021300.

The previous prime is 21216556021279. The next prime is 21216556021319. The reversal of 21216556021301 is 10312065561212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20132729276401 + 1083826744900 = 4486951^2 + 1041070^2 .

It is a cyclic number.

It is not a de Polignac number, because 21216556021301 - 2¹⁰ = 21216556020277 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21216556021321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608278010650 + 10608278010651.

It is an arithmetic number, because the mean of its divisors is an integer number (10608278010651).

Almost surely, 2^{21216556021301} is an apocalyptic number.

It is an amenable number.

21216556021301 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216556021301 is an equidigital number, since it uses as much as digits as its factorization.

21216556021301 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 35.

The spelling of 21216556021301 in words is "twenty-one trillion, two hundred sixteen billion, five hundred fifty-six million, twenty-one thousand, three hundred one".