1321708757 has 2 divisors, whose sum is σ = 1321708758. Its totient is φ = 1321708756.

The previous prime is 1321708721. The next prime is 1321708763. The reversal of 1321708757 is 7578071231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1124193841 + 197514916 = 33529^2 + 14054^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321708757 - 2¹⁰ = 1321707733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1321708357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660854378 + 660854379.

It is an arithmetic number, because the mean of its divisors is an integer number (660854379).

Almost surely, 2^1321708757 is an apocalyptic number.

It is an amenable number.

1321708757 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321708757 is an equidigital number, since it uses as much as digits as its factorization.

1321708757 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82320, while the sum is 41.

The square root of 1321708757 is about 36355.3126379075. The cubic root of 1321708757 is about 1097.4344498982.

Adding to 1321708757 its reverse (7578071231), we get a palindrome (8899779988).

The spelling of 1321708757 in words is "one billion, three hundred twenty-one million, seven hundred eight thousand, seven hundred fifty-seven".