7218985 has 4 divisors (see below), whose sum is σ = 8662788. Its totient is φ = 5775184.

The previous prime is 7218983. The next prime is 7218997. The reversal of 7218985 is 5898127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5898127 = 223 ⋅26449.

It can be written as a sum of positive squares in 2 ways, for example, as 2286144 + 4932841 = 1512^2 + 2221^2 .

It is a cyclic number.

It is not a de Polignac number, because 7218985 - 2¹ = 7218983 is a prime.

It is a super-2 number, since 2×7218985² = 104227488860450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 (7218983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 721894 + ... + 721903.

It is an arithmetic number, because the mean of its divisors is an integer number (2165697).

Almost surely, 2^7218985 is an apocalyptic number.

It is an amenable number.

7218985 is a deficient number, since it is larger than the sum of its proper divisors (1443803).

7218985 is a wasteful number, since it uses less digits than its factorization.

7218985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1443802.

The product of its digits is 40320, while the sum is 40.

The square root of 7218985 is about 2686.8168899276. The cubic root of 7218985 is about 193.2674484841.

The spelling of 7218985 in words is "seven million, two hundred eighteen thousand, nine hundred eighty-five".