212091209305 has 4 divisors (see below), whose sum is σ = 254509451172. Its totient is φ = 169672967440.

The previous prime is 212091209293. The next prime is 212091209357. The reversal of 212091209305 is 503902190212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 138100681161 + 73990528144 = 371619^2 + 272012^2 .

It is not a de Polignac number, because 212091209305 - 2¹⁷ = 212091078233 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21209120926 + ... + 21209120935.

It is an arithmetic number, because the mean of its divisors is an integer number (63627362793).

Almost surely, 2^212091209305 is an apocalyptic number.

It is an amenable number.

212091209305 is a deficient number, since it is larger than the sum of its proper divisors (42418241867).

212091209305 is an equidigital number, since it uses as much as digits as its factorization.

212091209305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42418241866.

The product of its (nonzero) digits is 9720, while the sum is 34.

Adding to 212091209305 its reverse (503902190212), we get a palindrome (715993399517).

The spelling of 212091209305 in words is "two hundred twelve billion, ninety-one million, two hundred nine thousand, three hundred five".