21121211233 has 4 divisors (see below), whose sum is σ = 21121524400. Its totient is φ = 21120898068.

The previous prime is 21121211117. The next prime is 21121211261. The reversal of 21121211233 is 33211212112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121211233 is a prime.

It is a super-2 number, since 2×21121211233² (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 21121211233.

It is not an unprimeable number, because it can be changed into a prime (21121211263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9135 + ... + 205732.

It is an arithmetic number, because the mean of its divisors is an integer number (5280381100).

Almost surely, 2^21121211233 is an apocalyptic number.

It is an amenable number.

21121211233 is a deficient number, since it is larger than the sum of its proper divisors (313167).

21121211233 is an equidigital number, since it uses as much as digits as its factorization.

21121211233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313166.

The product of its digits is 144, while the sum is 19.

Adding to 21121211233 its reverse (33211212112), we get a palindrome (54332423345).

It can be divided in two parts, 211212112 and 33, that multiplied together give a palindrome (6969999696).

The spelling of 21121211233 in words is "twenty-one billion, one hundred twenty-one million, two hundred eleven thousand, two hundred thirty-three".