66511216 has 40 divisors (see below), whose sum is σ = 135482400. Its totient is φ = 31570176.

The previous prime is 66511183. The next prime is 66511219. The reversal of 66511216 is 61211566.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66511219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54226 + ... + 55438.

It is an arithmetic number, because the mean of its divisors is an integer number (3387060).

Almost surely, 2^66511216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66511216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67741200).

66511216 is an abundant number, since it is smaller than the sum of its proper divisors (68971184).

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

66511216 is a wasteful number, since it uses less digits than its factorization.

66511216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1393 (or 1387 counting only the distinct ones).

The product of its digits is 2160, while the sum is 28.

The square root of 66511216 is about 8155.4408832386. The cubic root of 66511216 is about 405.1647269756.

It can be divided in two parts, 665 and 11216, that added together give a square (11881 = 109²).

The spelling of 66511216 in words is "sixty-six million, five hundred eleven thousand, two hundred sixteen".