7218491904 has 240 divisors, whose sum is σ = 23271760512. Its totient is φ = 2220576768.

The previous prime is 7218491899. The next prime is 7218491909. The reversal of 7218491904 is 4091948127.

It is a happy number.

7218491904 is a `hidden beast` number, since 72 + 1 + 8 + 491 + 90 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (7218491899) and next prime (7218491909).

It is a super-2 number, since 2×7218491904² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 7218491904.

It is not an unprimeable number, because it can be changed into a prime (7218491909) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1615177 + ... + 1619639.

Almost surely, 2^7218491904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7218491904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11635880256).

7218491904 is an abundant number, since it is smaller than the sum of its proper divisors (16053268608).

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

7218491904 is an equidigital number, since it uses as much as digits as its factorization.

7218491904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4509 (or 4481 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 7218491904 is about 84961.7084573986. The cubic root of 7218491904 is about 1932.6304797744.

The spelling of 7218491904 in words is "seven billion, two hundred eighteen million, four hundred ninety-one thousand, nine hundred four".