1221011121021 has 4 divisors (see below), whose sum is σ = 1628014828032. Its totient is φ = 814007414012.

The previous prime is 1221011120983. The next prime is 1221011121023. The reversal of 1221011121021 is 1201211101221.

It is a happy number.

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 1221011121021 - 2⁶ = 1221011120957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221011121023) 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, 203501853501 + ... + 203501853506.

It is an arithmetic number, because the mean of its divisors is an integer number (407003707008).

Almost surely, 2^{1221011121021} is an apocalyptic number.

It is an amenable number.

1221011121021 is a deficient number, since it is larger than the sum of its proper divisors (407003707011).

1221011121021 is an equidigital number, since it uses as much as digits as its factorization.

1221011121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407003707010.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1221011121021 its reverse (1201211101221), we get a palindrome (2422222222242).

The spelling of 1221011121021 in words is "one trillion, two hundred twenty-one billion, eleven million, one hundred twenty-one thousand, twenty-one".