1221202120121 has 16 divisors (see below), whose sum is σ = 1250964494400. Its totient is φ = 1191756017088.

The previous prime is 1221202120013. The next prime is 1221202120141. The reversal of 1221202120121 is 1210212021221.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221202120121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221202120121.

It is not an unprimeable number, because it can be changed into a prime (1221202120141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10064150 + ... + 10184768.

It is an arithmetic number, because the mean of its divisors is an integer number (78185280900).

Almost surely, 2^{1221202120121} is an apocalyptic number.

It is an amenable number.

1221202120121 is a deficient number, since it is larger than the sum of its proper divisors (29762374279).

1221202120121 is a wasteful number, since it uses less digits than its factorization.

1221202120121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121928.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1221202120121 its reverse (1210212021221), we get a palindrome (2431414141342).

The spelling of 1221202120121 in words is "one trillion, two hundred twenty-one billion, two hundred two million, one hundred twenty thousand, one hundred twenty-one".