66915772 has 72 divisors (see below), whose sum is σ = 152430768. Its totient is φ = 25401600.

The previous prime is 66915769. The next prime is 66915773. The reversal of 66915772 is 27751966.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66915773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88018 + ... + 88774.

It is an arithmetic number, because the mean of its divisors is an integer number (2117094).

Almost surely, 2^66915772 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 66915772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76215384).

66915772 is an abundant number, since it is smaller than the sum of its proper divisors (85514996).

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

66915772 is a wasteful number, since it uses less digits than its factorization.

66915772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 827 (or 818 counting only the distinct ones).

The product of its digits is 158760, while the sum is 43.

The square root of 66915772 is about 8180.2061098728. The cubic root of 66915772 is about 405.9845416231.

The spelling of 66915772 in words is "sixty-six million, nine hundred fifteen thousand, seven hundred seventy-two".