216065664 has 128 divisors (see below), whose sum is σ = 645048000. Its totient is φ = 71193600.

The previous prime is 216065651. The next prime is 216065693. The reversal of 216065664 is 466560612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 348747 + ... + 349365.

Almost surely, 2^216065664 is an apocalyptic number.

216065664 is a gapful number since it is divisible by the number (24) 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 216065664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (322524000).

216065664 is an abundant number, since it is smaller than the sum of its proper divisors (428982336).

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

216065664 is a wasteful number, since it uses less digits than its factorization.

216065664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 743 (or 725 counting only the distinct ones).

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

The square root of 216065664 is about 14699.1722215913. The cubic root of 216065664 is about 600.0607938400.

The spelling of 216065664 in words is "two hundred sixteen million, sixty-five thousand, six hundred sixty-four".