1221240121 has 2 divisors, whose sum is σ = 1221240122. Its totient is φ = 1221240120.

The previous prime is 1221240109. The next prime is 1221240149. The reversal of 1221240121 is 1210421221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 752734096 + 468506025 = 27436^2 + 21645^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221240121 - 2⁵ = 1221240089 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221240095 and 1221240104.

It is not a weakly prime, because it can be changed into another prime (1221240221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610620060 + 610620061.

It is an arithmetic number, because the mean of its divisors is an integer number (610620061).

Almost surely, 2^1221240121 is an apocalyptic number.

It is an amenable number.

1221240121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221240121 is an equidigital number, since it uses as much as digits as its factorization.

1221240121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 1221240121 is about 34946.2461646455. The cubic root of 1221240121 is about 1068.8916584068.

Adding to 1221240121 its reverse (1210421221), we get a palindrome (2431661342).

The spelling of 1221240121 in words is "one billion, two hundred twenty-one million, two hundred forty thousand, one hundred twenty-one".