66656020 has 48 divisors (see below), whose sum is σ = 144365760. Its totient is φ = 25837056.

The previous prime is 66655999. The next prime is 66656027. The reversal of 66656020 is 2065666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66656027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 153724 + ... + 154156.

It is an arithmetic number, because the mean of its divisors is an integer number (3007620).

Almost surely, 2^66656020 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 66656020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72182880).

66656020 is an abundant number, since it is smaller than the sum of its proper divisors (77709740).

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

66656020 is a wasteful number, since it uses less digits than its factorization.

66656020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664 (or 662 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 66656020 is about 8164.3138107253. The cubic root of 66656020 is about 405.4585468300.

The spelling of 66656020 in words is "sixty-six million, six hundred fifty-six thousand, twenty".