1321512121 has 2 divisors, whose sum is σ = 1321512122. Its totient is φ = 1321512120.

The previous prime is 1321512097. The next prime is 1321512131. The reversal of 1321512121 is 1212151231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 837292096 + 484220025 = 28936^2 + 22005^2 .

It is an emirp because it is prime and its reverse (1212151231) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1321512121 - 2⁷ = 1321511993 is a prime.

It is not a weakly prime, because it can be changed into another prime (1321512131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660756060 + 660756061.

It is an arithmetic number, because the mean of its divisors is an integer number (660756061).

Almost surely, 2^1321512121 is an apocalyptic number.

It is an amenable number.

1321512121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321512121 is an equidigital number, since it uses as much as digits as its factorization.

1321512121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120, while the sum is 19.

The square root of 1321512121 is about 36352.6081732797. The cubic root of 1321512121 is about 1097.3800239334.

Adding to 1321512121 its reverse (1212151231), we get a palindrome (2533663352).

The spelling of 1321512121 in words is "one billion, three hundred twenty-one million, five hundred twelve thousand, one hundred twenty-one".