7218540 has 144 divisors (see below), whose sum is σ = 26574912. Its totient is φ = 1548288.

The previous prime is 7218529. The next prime is 7218551. The reversal of 7218540 is 458127.

It is an interprime number because it is at equal distance from previous prime (7218529) and next prime (7218551).

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21252 + ... + 21588.

It is an arithmetic number, because the mean of its divisors is an integer number (184548).

Almost surely, 2^7218540 is an apocalyptic number.

7218540 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7218540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13287456).

7218540 is an abundant number, since it is smaller than the sum of its proper divisors (19356372).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

7218540 is a wasteful number, since it uses less digits than its factorization.

7218540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 7218540 is about 2686.7340769045. The cubic root of 7218540 is about 193.2634772065.

It can be divided in two parts, 721 and 8540, that added together give a cube (9261 = 21³).

The spelling of 7218540 in words is "seven million, two hundred eighteen thousand, five hundred forty".