211161571721 has 2 divisors, whose sum is σ = 211161571722. Its totient is φ = 211161571720.

The previous prime is 211161571711. The next prime is 211161571757. The reversal of 211161571721 is 127175161112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 200972890000 + 10188681721 = 448300^2 + 100939^2 .

It is a cyclic number.

It is not a de Polignac number, because 211161571721 - 2²⁶ = 211094462857 is a prime.

It is not a weakly prime, because it can be changed into another prime (211161571711) 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, 105580785860 + 105580785861.

It is an arithmetic number, because the mean of its divisors is an integer number (105580785861).

Almost surely, 2^211161571721 is an apocalyptic number.

It is an amenable number.

211161571721 is a deficient number, since it is larger than the sum of its proper divisors (1).

211161571721 is an equidigital number, since it uses as much as digits as its factorization.

211161571721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5880, while the sum is 35.

The spelling of 211161571721 in words is "two hundred eleven billion, one hundred sixty-one million, five hundred seventy-one thousand, seven hundred twenty-one".