7218889 has 2 divisors, whose sum is σ = 7218890. Its totient is φ = 7218888.

The previous prime is 7218859. The next prime is 7218899. The reversal of 7218889 is 9888127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6335289 + 883600 = 2517^2 + 940^2 .

It is an emirp because it is prime and its reverse (9888127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7218889 - 2²¹ = 5121737 is a prime.

It is a super-2 number, since 2×7218889² = 104224716788642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7218839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3609444 + 3609445.

It is an arithmetic number, because the mean of its divisors is an integer number (3609445).

Almost surely, 2^7218889 is an apocalyptic number.

It is an amenable number.

7218889 is a deficient number, since it is larger than the sum of its proper divisors (1).

7218889 is an equidigital number, since it uses as much as digits as its factorization.

7218889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 43.

The square root of 7218889 is about 2686.7990248621. The cubic root of 7218889 is about 193.2665917729.

The spelling of 7218889 in words is "seven million, two hundred eighteen thousand, eight hundred eighty-nine".