211221210305 has 24 divisors (see below), whose sum is σ = 295896943080. Its totient is φ = 144321918720.

The previous prime is 211221210271. The next prime is 211221210323. The reversal of 211221210305 is 503012122112.

It can be written as a sum of positive squares in 4 ways, for example, as 45884638849 + 165336571456 = 214207^2 + 406616^2 .

It is not a de Polignac number, because 211221210305 - 2⁸ = 211221210049 is a prime.

It is a super-2 number, since 2×211221210305² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1465190 + ... + 1602879.

It is an arithmetic number, because the mean of its divisors is an integer number (12329039295).

Almost surely, 2^211221210305 is an apocalyptic number.

It is an amenable number.

211221210305 is a deficient number, since it is larger than the sum of its proper divisors (84675732775).

211221210305 is a wasteful number, since it uses less digits than its factorization.

211221210305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3068369 (or 3068362 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 211221210305 its reverse (503012122112), we get a palindrome (714233332417).

The spelling of 211221210305 in words is "two hundred eleven billion, two hundred twenty-one million, two hundred ten thousand, three hundred five".