7018721 has 4 divisors (see below), whose sum is σ = 7133844. Its totient is φ = 6903600.

The previous prime is 7018709. The next prime is 7018747. The reversal of 7018721 is 1278107.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 541696 + 6477025 = 736^2 + 2545^2 .

It is a cyclic number.

It is not a de Polignac number, because 7018721 - 2¹⁰ = 7017697 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7018751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57470 + ... + 57591.

It is an arithmetic number, because the mean of its divisors is an integer number (1783461).

Almost surely, 2^7018721 is an apocalyptic number.

It is an amenable number.

7018721 is a deficient number, since it is larger than the sum of its proper divisors (115123).

7018721 is a wasteful number, since it uses less digits than its factorization.

7018721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115122.

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

The square root of 7018721 is about 2649.2868851825. The cubic root of 7018721 is about 191.4634997367.

The spelling of 7018721 in words is "seven million, eighteen thousand, seven hundred twenty-one".