7830721 has 2 divisors, whose sum is σ = 7830722. Its totient is φ = 7830720.

The previous prime is 7830707. The next prime is 7830731. The reversal of 7830721 is 1270387.

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., 5760000 + 2070721 = 2400^2 + 1439^2 .

It is a cyclic number.

It is not a de Polignac number, because 7830721 - 2⁷ = 7830593 is a prime.

It is a super-2 number, since 2×7830721² = 122640382759682, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 7830721.

It is not a weakly prime, because it can be changed into another prime (7830701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3915360 + 3915361.

It is an arithmetic number, because the mean of its divisors is an integer number (3915361).

Almost surely, 2^7830721 is an apocalyptic number.

It is an amenable number.

7830721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7830721 is an equidigital number, since it uses as much as digits as its factorization.

7830721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 7830721 is about 2798.3425451506. The cubic root of 7830721 is about 198.5792732414.

The spelling of 7830721 in words is "seven million, eight hundred thirty thousand, seven hundred twenty-one".