7218545 has 4 divisors (see below), whose sum is σ = 8662260. Its totient is φ = 5774832.

The previous prime is 7218529. The next prime is 7218551. The reversal of 7218545 is 5458127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5458127 = 1439 ⋅3793.

It can be written as a sum of positive squares in 2 ways, for example, as 3341584 + 3876961 = 1828^2 + 1969^2 .

It is a cyclic number.

It is not a de Polignac number, because 7218545 - 2⁴ = 7218529 is a prime.

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

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 721850 + ... + 721859.

It is an arithmetic number, because the mean of its divisors is an integer number (2165565).

Almost surely, 2^7218545 is an apocalyptic number.

It is an amenable number.

7218545 is a deficient number, since it is larger than the sum of its proper divisors (1443715).

7218545 is a wasteful number, since it uses less digits than its factorization.

7218545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1443714.

The product of its digits is 11200, while the sum is 32.

The square root of 7218545 is about 2686.7350074021. The cubic root of 7218545 is about 193.2635218285.

The spelling of 7218545 in words is "seven million, two hundred eighteen thousand, five hundred forty-five".