1221002120121 has 32 divisors (see below), whose sum is σ = 1868916876288. Its totient is φ = 694592729280.

The previous prime is 1221002120119. The next prime is 1221002120171. The reversal of 1221002120121 is 1210212001221.

It is not a de Polignac number, because 1221002120121 - 2¹ = 1221002120119 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221002120121.

It is not an unprimeable number, because it can be changed into a prime (1221002120171) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5177646 + ... + 5408328.

It is an arithmetic number, because the mean of its divisors is an integer number (58403652384).

Almost surely, 2^{1221002120121} is an apocalyptic number.

It is an amenable number.

1221002120121 is a deficient number, since it is larger than the sum of its proper divisors (647914756167).

1221002120121 is a wasteful number, since it uses less digits than its factorization.

1221002120121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231821.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1221002120121 its reverse (1210212001221), we get a palindrome (2431214121342).

The spelling of 1221002120121 in words is "one trillion, two hundred twenty-one billion, two million, one hundred twenty thousand, one hundred twenty-one".