1221210012121 has 4 divisors (see below), whose sum is σ = 1332229104144. Its totient is φ = 1110190920100.

The previous prime is 1221210012107. The next prime is 1221210012133. The reversal of 1221210012121 is 1212100121221.

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 not a de Polignac number, because 1221210012121 - 2⁷ = 1221210011993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221210012095 and 1221210012104.

It is not an unprimeable number, because it can be changed into a prime (1221210012181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55509545995 + ... + 55509546016.

It is an arithmetic number, because the mean of its divisors is an integer number (333057276036).

Almost surely, 2^{1221210012121} is an apocalyptic number.

1221210012121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221210012121 is a deficient number, since it is larger than the sum of its proper divisors (111019092023).

1221210012121 is a wasteful number, since it uses less digits than its factorization.

1221210012121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111019092022.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221210012121 its reverse (1212100121221), we get a palindrome (2433310133342).

It can be divided in two parts, 1 and 221210012121, that added together give a palindrome (221210012122).

The spelling of 1221210012121 in words is "one trillion, two hundred twenty-one billion, two hundred ten million, twelve thousand, one hundred twenty-one".