21221311211 has 8 divisors (see below), whose sum is σ = 21509582400. Its totient is φ = 20934147520.

The previous prime is 21221311201. The next prime is 21221311213. The reversal of 21221311211 is 11211312212.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221311211 is a prime.

It is a super-2 number, since 2×21221311211² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21221311211.

It is not an unprimeable number, because it can be changed into a prime (21221311213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 238256 + ... + 314973.

It is an arithmetic number, because the mean of its divisors is an integer number (2688697800).

Almost surely, 2^21221311211 is an apocalyptic number.

21221311211 is a deficient number, since it is larger than the sum of its proper divisors (288271189).

21221311211 is an equidigital number, since it uses as much as digits as its factorization.

21221311211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553749.

The product of its digits is 48, while the sum is 17.

Adding to 21221311211 its reverse (11211312212), we get a palindrome (32432623423).

The spelling of 21221311211 in words is "twenty-one billion, two hundred twenty-one million, three hundred eleven thousand, two hundred eleven".