66644020 has 48 divisors (see below), whose sum is σ = 149163840. Its totient is φ = 24938496.

The previous prime is 66643933. The next prime is 66644033. The reversal of 66644020 is 2044666.

It is a self number, because there is not a number n which added to its sum of digits gives 66644020.

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, 30484 + ... + 32596.

It is an arithmetic number, because the mean of its divisors is an integer number (3107580).

Almost surely, 2^66644020 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 66644020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74581920).

66644020 is an abundant number, since it is smaller than the sum of its proper divisors (82519820).

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

66644020 is a wasteful number, since it uses less digits than its factorization.

66644020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2224 (or 2222 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 66644020 is about 8163.5788720389. The cubic root of 66644020 is about 405.4342139712.

Adding to 66644020 its reverse (2044666), we get a palindrome (68688686).

The spelling of 66644020 in words is "sixty-six million, six hundred forty-four thousand, twenty".