66199980 has 288 divisors, whose sum is σ = 248209920. Its totient is φ = 13009920.

The previous prime is 66199979. The next prime is 66199981. The reversal of 66199980 is 8999166.

66199980 is digitally balanced in base 2 and base 9, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (66199979) and next prime (66199981).

66199980 is strictly pandigital in base 9.

It is not an unprimeable number, because it can be changed into a prime (66199981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 743776 + ... + 743864.

It is an arithmetic number, because the mean of its divisors is an integer number (861840).

Almost surely, 2^66199980 is an apocalyptic number.

66199980 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66199980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124104960).

66199980 is an abundant number, since it is smaller than the sum of its proper divisors (182009940).

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

66199980 is a wasteful number, since it uses less digits than its factorization.

66199980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 140 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 48.

The square root of 66199980 is about 8136.3370136690. The cubic root of 66199980 is about 404.5317557500.

The spelling of 66199980 in words is "sixty-six million, one hundred ninety-nine thousand, nine hundred eighty".