216609400 has 216 divisors, whose sum is σ = 631667160. Its totient is φ = 68745600.

The previous prime is 216609391. The next prime is 216609401. The reversal of 216609400 is 4906612.

216609400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216609401) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 6987385 + ... + 6987415.

It is an arithmetic number, because the mean of its divisors is an integer number (2924385).

Almost surely, 2^216609400 is an apocalyptic number.

216609400 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 216609400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315833580).

216609400 is an abundant number, since it is smaller than the sum of its proper divisors (415057760).

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

216609400 is a wasteful number, since it uses less digits than its factorization.

216609400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 216609400 is about 14717.6560633818. The cubic root of 216609400 is about 600.5637294419.

The spelling of 216609400 in words is "two hundred sixteen million, six hundred nine thousand, four hundred".