1321200121 has 2 divisors, whose sum is σ = 1321200122. Its totient is φ = 1321200120.

The previous prime is 1321200103. The next prime is 1321200137. The reversal of 1321200121 is 1210021231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1071907600 + 249292521 = 32740^2 + 15789^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321200121 - 2¹⁷ = 1321069049 is a prime.

It is a super-3 number, since 3×1321200121³ (a number of 28 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1321200161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660600060 + 660600061.

It is an arithmetic number, because the mean of its divisors is an integer number (660600061).

Almost surely, 2^1321200121 is an apocalyptic number.

It is an amenable number.

1321200121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321200121 is an equidigital number, since it uses as much as digits as its factorization.

1321200121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1321200121 is about 36348.3166185176. The cubic root of 1321200121 is about 1097.2936558226.

Adding to 1321200121 its reverse (1210021231), we get a palindrome (2531221352).

The spelling of 1321200121 in words is "one billion, three hundred twenty-one million, two hundred thousand, one hundred twenty-one".