1221121212011 has 4 divisors (see below), whose sum is σ = 1221578392224. Its totient is φ = 1220664031800.

The previous prime is 1221121211983. The next prime is 1221121212067. The reversal of 1221121212011 is 1102121211221.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221121212011 is a prime.

It is a super-2 number, since 2×1221121212011² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221121212511) 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, 228586100 + ... + 228591441.

It is an arithmetic number, because the mean of its divisors is an integer number (305394598056).

Almost surely, 2^{1221121212011} is an apocalyptic number.

1221121212011 is a deficient number, since it is larger than the sum of its proper divisors (457180213).

1221121212011 is an equidigital number, since it uses as much as digits as its factorization.

1221121212011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457180212.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1221121212011 its reverse (1102121211221), we get a palindrome (2323242423232).

The spelling of 1221121212011 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred twelve thousand, eleven".