66655021620 has 48 divisors (see below), whose sum is σ = 203600795328. Its totient is φ = 16158792960.

The previous prime is 66655021561. The next prime is 66655021621. The reversal of 66655021620 is 2612055666.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66655021621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50495569 + ... + 50496888.

It is an arithmetic number, because the mean of its divisors is an integer number (4241683236).

Almost surely, 2^66655021620 is an apocalyptic number.

66655021620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66655021620 is an abundant number, since it is smaller than the sum of its proper divisors (136945773708).

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

66655021620 is a wasteful number, since it uses less digits than its factorization.

66655021620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100992480 (or 100992478 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 39.

The spelling of 66655021620 in words is "sixty-six billion, six hundred fifty-five million, twenty-one thousand, six hundred twenty".