218155991040 has 840 divisors, whose sum is σ = 848369872728. Its totient is φ = 53508833280.

The previous prime is 218155991033. The next prime is 218155991041. The reversal of 218155991040 is 40199551812.

218155991040 is a `hidden beast` number, since 2 + 1 + 8 + 1 + 5 + 599 + 10 + 40 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10044850176 + 208111140864 = 100224^2 + 456192^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218155991041) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 776355700 + ... + 776355980.

Almost surely, 2^218155991040 is an apocalyptic number.

218155991040 is a gapful number since it is divisible by the number (20) 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 218155991040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (424184936364).

218155991040 is an abundant number, since it is smaller than the sum of its proper divisors (630213881688).

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

218155991040 is an frugal number, since it uses more digits than its factorization.

218155991040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345 (or 304 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 45.

The spelling of 218155991040 in words is "two hundred eighteen billion, one hundred fifty-five million, nine hundred ninety-one thousand, forty".