1318600721 has 2 divisors, whose sum is σ = 1318600722. Its totient is φ = 1318600720.

The previous prime is 1318600663. The next prime is 1318600757. The reversal of 1318600721 is 1270068131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 778689025 + 539911696 = 27905^2 + 23236^2 .

It is a cyclic number.

It is not a de Polignac number, because 1318600721 - 2¹⁰ = 1318599697 is a prime.

It is a super-2 number, since 2×1318600721² = 3477415722843439682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1318600781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 659300360 + 659300361.

It is an arithmetic number, because the mean of its divisors is an integer number (659300361).

Almost surely, 2^1318600721 is an apocalyptic number.

It is an amenable number.

1318600721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1318600721 is an equidigital number, since it uses as much as digits as its factorization.

1318600721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 1318600721 is about 36312.5421996312. The cubic root of 1318600721 is about 1096.5735585606.

Adding to 1318600721 its reverse (1270068131), we get a palindrome (2588668852).

The spelling of 1318600721 in words is "one billion, three hundred eighteen million, six hundred thousand, seven hundred twenty-one".