1321121257 has 2 divisors, whose sum is σ = 1321121258. Its totient is φ = 1321121256.

The previous prime is 1321121239. The next prime is 1321121267. The reversal of 1321121257 is 7521211231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1311236521 + 9884736 = 36211^2 + 3144^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1321121257 is a prime.

It is a super-2 number, since 2×1321121257² = 3490722751394520098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1321121267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660560628 + 660560629.

It is an arithmetic number, because the mean of its divisors is an integer number (660560629).

Almost surely, 2^1321121257 is an apocalyptic number.

It is an amenable number.

1321121257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321121257 is an equidigital number, since it uses as much as digits as its factorization.

1321121257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 25.

The square root of 1321121257 is about 36347.2317652940. The cubic root of 1321121257 is about 1097.2718224689.

Adding to 1321121257 its reverse (7521211231), we get a palindrome (8842332488).

The spelling of 1321121257 in words is "one billion, three hundred twenty-one million, one hundred twenty-one thousand, two hundred fifty-seven".