7180721 has 2 divisors, whose sum is σ = 7180722. Its totient is φ = 7180720.

The previous prime is 7180717. The next prime is 7180729. The reversal of 7180721 is 1270817.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4494400 + 2686321 = 2120^2 + 1639^2 .

It is an emirp because it is prime and its reverse (1270817) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7180721 - 2² = 7180717 is a prime.

It is not a weakly prime, because it can be changed into another prime (7180729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3590360 + 3590361.

It is an arithmetic number, because the mean of its divisors is an integer number (3590361).

Almost surely, 2^7180721 is an apocalyptic number.

It is an amenable number.

7180721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7180721 is an equidigital number, since it uses as much as digits as its factorization.

7180721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 784, while the sum is 26.

The square root of 7180721 is about 2679.6867354226. The cubic root of 7180721 is about 192.9253740677.

The spelling of 7180721 in words is "seven million, one hundred eighty thousand, seven hundred twenty-one".