218858640 has 320 divisors, whose sum is σ = 911941632. Its totient is φ = 41932800.

The previous prime is 218858581. The next prime is 218858641. The reversal of 218858640 is 46858812.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 218858592 and 218858601.

It is not an unprimeable number, because it can be changed into a prime (218858641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 239785 + ... + 240695.

Almost surely, 2^218858640 is an apocalyptic number.

218858640 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 218858640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (455970816).

218858640 is an abundant number, since it is smaller than the sum of its proper divisors (693082992).

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

218858640 is a wasteful number, since it uses less digits than its factorization.

218858640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958 (or 952 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 42.

The square root of 218858640 is about 14793.8717041889. The cubic root of 218858640 is about 602.6352972900.

It can be divided in two parts, 218 and 858640, that added together give a palindrome (858858).

The spelling of 218858640 in words is "two hundred eighteen million, eight hundred fifty-eight thousand, six hundred forty".