1212211111221 has 32 divisors (see below), whose sum is σ = 1959345959040. Its totient is φ = 734592067200.

The previous prime is 1212211111211. The next prime is 1212211111231. The reversal of 1212211111221 is 1221111122121.

It is a happy number.

1212211111221 is a `hidden beast` number, since 121 + 2 + 211 + 111 + 221 = 666.

It is an interprime number because it is at equal distance from previous prime (1212211111211) and next prime (1212211111231).

It is not a de Polignac number, because 1212211111221 - 2⁶ = 1212211111157 is a prime.

It is a super-2 number, since 2×1212211111221² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1212211111194 and 1212211111203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212211111211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2517321 + ... + 2959953.

It is an arithmetic number, because the mean of its divisors is an integer number (61229561220).

Almost surely, 2^{1212211111221} is an apocalyptic number.

1212211111221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1212211111221 is a deficient number, since it is larger than the sum of its proper divisors (747134847819).

1212211111221 is a wasteful number, since it uses less digits than its factorization.

1212211111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451874 (or 451868 counting only the distinct ones).

The product of its digits is 32, while the sum is 18.

Adding to 1212211111221 its reverse (1221111122121), we get a palindrome (2433322233342).

The spelling of 1212211111221 in words is "one trillion, two hundred twelve billion, two hundred eleven million, one hundred eleven thousand, two hundred twenty-one".