66223640 has 64 divisors (see below), whose sum is σ = 171452160. Its totient is φ = 22550400.

The previous prime is 66223639. The next prime is 66223681. The reversal of 66223640 is 4632266.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44915 + ... + 46365.

It is an arithmetic number, because the mean of its divisors is an integer number (2678940).

Almost surely, 2^66223640 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 66223640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85726080).

66223640 is an abundant number, since it is smaller than the sum of its proper divisors (105228520).

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

66223640 is a wasteful number, since it uses less digits than its factorization.

66223640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632 (or 1628 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 66223640 is about 8137.7908550171. The cubic root of 66223640 is about 404.5799434851.

The spelling of 66223640 in words is "sixty-six million, two hundred twenty-three thousand, six hundred forty".