1257722321 has 2 divisors, whose sum is σ = 1257722322. Its totient is φ = 1257722320.

The previous prime is 1257722299. The next prime is 1257722327. The reversal of 1257722321 is 1232277521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1232361025 + 25361296 = 35105^2 + 5036^2 .

It is a cyclic number.

It is not a de Polignac number, because 1257722321 - 2¹⁴ = 1257705937 is a prime.

It is not a weakly prime, because it can be changed into another prime (1257722327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628861160 + 628861161.

It is an arithmetic number, because the mean of its divisors is an integer number (628861161).

Almost surely, 2^1257722321 is an apocalyptic number.

It is an amenable number.

1257722321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1257722321 is an equidigital number, since it uses as much as digits as its factorization.

1257722321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11760, while the sum is 32.

The square root of 1257722321 is about 35464.3810181427. The cubic root of 1257722321 is about 1079.4310906873.

Adding to 1257722321 its reverse (1232277521), we get a palindrome (2489999842).

The spelling of 1257722321 in words is "one billion, two hundred fifty-seven million, seven hundred twenty-two thousand, three hundred twenty-one".