1221002010121 has 4 divisors (see below), whose sum is σ = 1221104549700. Its totient is φ = 1220899470544.

The previous prime is 1221002010049. The next prime is 1221002010149. The reversal of 1221002010121 is 1210102001221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 238276754496 + 982725255625 = 488136^2 + 991325^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221002010121 - 2¹¹ = 1221002008073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221002010161) 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, 51251926 + ... + 51275743.

It is an arithmetic number, because the mean of its divisors is an integer number (305276137425).

Almost surely, 2^{1221002010121} is an apocalyptic number.

It is an amenable number.

1221002010121 is a deficient number, since it is larger than the sum of its proper divisors (102539579).

1221002010121 is a wasteful number, since it uses less digits than its factorization.

1221002010121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102539578.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1221002010121 its reverse (1210102001221), we get a palindrome (2431104011342).

The spelling of 1221002010121 in words is "one trillion, two hundred twenty-one billion, two million, ten thousand, one hundred twenty-one".