218861400 has 192 divisors, whose sum is σ = 736560000. Its totient is φ = 53544960.

The previous prime is 218861393. The next prime is 218861407. The reversal of 218861400 is 4168812.

218861400 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (218861393) and next prime (218861407).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218861407) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 438351 + ... + 438849.

It is an arithmetic number, because the mean of its divisors is an integer number (3836250).

Almost surely, 2^218861400 is an apocalyptic number.

218861400 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 218861400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (368280000).

218861400 is an abundant number, since it is smaller than the sum of its proper divisors (517698600).

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

218861400 is a wasteful number, since it uses less digits than its factorization.

218861400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 578 (or 569 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 218861400 is about 14793.9649857636. The cubic root of 218861400 is about 602.6378305331.

The spelling of 218861400 in words is "two hundred eighteen million, eight hundred sixty-one thousand, four hundred".