7218881 has 4 divisors (see below), whose sum is σ = 7225812. Its totient is φ = 7211952.

The previous prime is 7218859. The next prime is 7218889. The reversal of 7218881 is 1888127.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1888127 = 67 ⋅28181.

It can be written as a sum of positive squares in 2 ways, for example, as 5216656 + 2002225 = 2284^2 + 1415^2 .

It is a cyclic number.

It is not a de Polignac number, because 7218881 - 2⁶ = 7218817 is a prime.

It is a super-2 number, since 2×7218881² = 104224485784322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7218889) 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, 1550 + ... + 4103.

It is an arithmetic number, because the mean of its divisors is an integer number (1806453).

Almost surely, 2^7218881 is an apocalyptic number.

It is an amenable number.

7218881 is a deficient number, since it is larger than the sum of its proper divisors (6931).

7218881 is a wasteful number, since it uses less digits than its factorization.

7218881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6930.

The product of its digits is 7168, while the sum is 35.

The square root of 7218881 is about 2686.7975361013. The cubic root of 7218881 is about 193.2665203799.

The spelling of 7218881 in words is "seven million, two hundred eighteen thousand, eight hundred eighty-one".