7218131 has 4 divisors (see below), whose sum is σ = 7270200. Its totient is φ = 7166064.

The previous prime is 7218121. The next prime is 7218139. The reversal of 7218131 is 1318127.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1318127 = 197 ⋅6691.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7218131 is a prime.

It is a super-2 number, since 2×7218131² = 104202830266322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 7218097 and 7218106.

It is not an unprimeable number, because it can be changed into a prime (7218139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25826 + ... + 26103.

It is an arithmetic number, because the mean of its divisors is an integer number (1817550).

Almost surely, 2^7218131 is an apocalyptic number.

7218131 is a deficient number, since it is larger than the sum of its proper divisors (52069).

7218131 is a wasteful number, since it uses less digits than its factorization.

7218131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52068.

The product of its digits is 336, while the sum is 23.

The square root of 7218131 is about 2686.6579611108. The cubic root of 7218131 is about 193.2598270568.

The spelling of 7218131 in words is "seven million, two hundred eighteen thousand, one hundred thirty-one".