1318721 has 2 divisors, whose sum is σ = 1318722. Its totient is φ = 1318720.

The previous prime is 1318711. The next prime is 1318727. The reversal of 1318721 is 1278131.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 739600 + 579121 = 860^2 + 761^2 .

It is an emirp because it is prime and its reverse (1278131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1318721 - 2¹⁰ = 1317697 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1318727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 659360 + 659361.

It is an arithmetic number, because the mean of its divisors is an integer number (659361).

2^1318721 is an apocalyptic number.

It is an amenable number.

1318721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1318721 is an equidigital number, since it uses as much as digits as its factorization.

1318721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 336, while the sum is 23.

The square root of 1318721 is about 1148.3557811062. The cubic root of 1318721 is about 109.6606899652.

The spelling of 1318721 in words is "one million, three hundred eighteen thousand, seven hundred twenty-one".