211655542421 has 2 divisors, whose sum is σ = 211655542422. Its totient is φ = 211655542420.

The previous prime is 211655542339. The next prime is 211655542457. The reversal of 211655542421 is 124245556112.

211655542421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 210946385521 + 709156900 = 459289^2 + 26630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211655542421 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 (211655542481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105827771210 + 105827771211.

It is an arithmetic number, because the mean of its divisors is an integer number (105827771211).

Almost surely, 2^211655542421 is an apocalyptic number.

It is an amenable number.

211655542421 is a deficient number, since it is larger than the sum of its proper divisors (1).

211655542421 is an equidigital number, since it uses as much as digits as its factorization.

211655542421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96000, while the sum is 38.

The spelling of 211655542421 in words is "two hundred eleven billion, six hundred fifty-five million, five hundred forty-two thousand, four hundred twenty-one".