21221201211 has 48 divisors (see below), whose sum is σ = 34083309600. Its totient is φ = 11696627712.

The previous prime is 21221201191. The next prime is 21221201231. The reversal of 21221201211 is 11210212212.

It is an interprime number because it is at equal distance from previous prime (21221201191) and next prime (21221201231).

It is not a de Polignac number, because 21221201211 - 2¹⁵ = 21221168443 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21221201231) 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 in 47 ways as a sum of consecutive naturals, for example, 6004801 + ... + 6008333.

It is an arithmetic number, because the mean of its divisors is an integer number (710068950).

Almost surely, 2^21221201211 is an apocalyptic number.

21221201211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21221201211 is a deficient number, since it is larger than the sum of its proper divisors (12862108389).

21221201211 is a wasteful number, since it uses less digits than its factorization.

21221201211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4988 (or 4981 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21221201211 its reverse (11210212212), we get a palindrome (32431413423).

The spelling of 21221201211 in words is "twenty-one billion, two hundred twenty-one million, two hundred one thousand, two hundred eleven".