1221220121023 has 16 divisors (see below), whose sum is σ = 1461619560960. Its totient is φ = 997634141856.

The previous prime is 1221220121003. The next prime is 1221220121039. The reversal of 1221220121023 is 3201210221221.

It is not a de Polignac number, because 1221220121023 - 2³⁷ = 1083781167551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221220121003) 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, 13647133 + ... + 13736326.

It is an arithmetic number, because the mean of its divisors is an integer number (91351222560).

Almost surely, 2^{1221220121023} is an apocalyptic number.

1221220121023 is a deficient number, since it is larger than the sum of its proper divisors (240399439937).

1221220121023 is a wasteful number, since it uses less digits than its factorization.

1221220121023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27383766.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 1221220121023 its reverse (3201210221221), we get a palindrome (4422430342244).

The spelling of 1221220121023 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred twenty-one thousand, twenty-three".