211221043409 has 2 divisors, whose sum is σ = 211221043410. Its totient is φ = 211221043408.

The previous prime is 211221043381. The next prime is 211221043433. The reversal of 211221043409 is 904340122112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 191984185600 + 19236857809 = 438160^2 + 138697^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221043409 - 2¹² = 211221039313 is a prime.

It is a super-2 number, since 2×211221043409² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (211221043009) 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, 105610521704 + 105610521705.

It is an arithmetic number, because the mean of its divisors is an integer number (105610521705).

Almost surely, 2^211221043409 is an apocalyptic number.

It is an amenable number.

211221043409 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221043409 is an equidigital number, since it uses as much as digits as its factorization.

211221043409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The spelling of 211221043409 in words is "two hundred eleven billion, two hundred twenty-one million, forty-three thousand, four hundred nine".