121221002021 has 4 divisors (see below), whose sum is σ = 138538288032. Its totient is φ = 103903716012.

The previous prime is 121221001939. The next prime is 121221002069. The reversal of 121221002021 is 120200122121.

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, and also an emirpimes, since its reverse is a distinct semiprime: 120200122121 = 149 ⋅806712229.

It is a cyclic number.

It is not a de Polignac number, because 121221002021 - 2¹⁰ = 121221000997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 121221001987 and 121221002005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121221002321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8658642995 + ... + 8658643008.

It is an arithmetic number, because the mean of its divisors is an integer number (34634572008).

Almost surely, 2^121221002021 is an apocalyptic number.

It is an amenable number.

121221002021 is a deficient number, since it is larger than the sum of its proper divisors (17317286011).

121221002021 is an equidigital number, since it uses as much as digits as its factorization.

121221002021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17317286010.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 121221002021 its reverse (120200122121), we get a palindrome (241421124142).

The spelling of 121221002021 in words is "one hundred twenty-one billion, two hundred twenty-one million, two thousand, twenty-one".