7173721 has 2 divisors, whose sum is σ = 7173722. Its totient is φ = 7173720.

The previous prime is 7173703. The next prime is 7173737. The reversal of 7173721 is 1273717.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5760000 + 1413721 = 2400^2 + 1189^2 .

It is a cyclic number.

It is not a de Polignac number, because 7173721 - 2⁵ = 7173689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 7173721.

It is not a weakly prime, because it can be changed into another prime (7173781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3586860 + 3586861.

It is an arithmetic number, because the mean of its divisors is an integer number (3586861).

Almost surely, 2^7173721 is an apocalyptic number.

It is an amenable number.

7173721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7173721 is an equidigital number, since it uses as much as digits as its factorization.

7173721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2058, while the sum is 28.

The square root of 7173721 is about 2678.3802941330. The cubic root of 7173721 is about 192.8626637129.

The spelling of 7173721 in words is "seven million, one hundred seventy-three thousand, seven hundred twenty-one".