211221555445 has 8 divisors (see below), whose sum is σ = 256938002136. Its totient is φ = 166662487296.

The previous prime is 211221555427. The next prime is 211221555469. The reversal of 211221555445 is 544555122112.

211221555445 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 10536516 + 211211018929 = 3246^2 + 459577^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 211221555445 - 2¹³ = 211221547253 is a prime.

It is a super-2 number, since 2×211221555445² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 289344232 + ... + 289344961.

It is an arithmetic number, because the mean of its divisors is an integer number (32117250267).

Almost surely, 2^211221555445 is an apocalyptic number.

It is an amenable number.

211221555445 is a deficient number, since it is larger than the sum of its proper divisors (45716446691).

211221555445 is an equidigital number, since it uses as much as digits as its factorization.

211221555445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578689271.

The product of its digits is 80000, while the sum is 37.

Adding to 211221555445 its reverse (544555122112), we get a palindrome (755776677557).

The spelling of 211221555445 in words is "two hundred eleven billion, two hundred twenty-one million, five hundred fifty-five thousand, four hundred forty-five".