216666450 has 432 divisors, whose sum is σ = 807109056. Its totient is φ = 40435200.

The previous prime is 216666419. The next prime is 216666451. The reversal of 216666450 is 54666612.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (216666451) by changing a digit.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 5855832 + ... + 5855868.

It is an arithmetic number, because the mean of its divisors is an integer number (1868308).

Almost surely, 2^216666450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216666450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (403554528).

216666450 is an abundant number, since it is smaller than the sum of its proper divisors (590442606).

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

216666450 is a wasteful number, since it uses less digits than its factorization.

216666450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 216666450 is about 14719.5940840772. The cubic root of 216666450 is about 600.6164497659.

It can be divided in two parts, 216 and 666450, that added together give a palindrome (666666).

The spelling of 216666450 in words is "two hundred sixteen million, six hundred sixty-six thousand, four hundred fifty".