66755640 has 96 divisors (see below), whose sum is σ = 232984080. Its totient is φ = 15257088.

The previous prime is 66755627. The next prime is 66755641. The reversal of 66755640 is 4655766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66755641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 204 + ... + 11556.

Almost surely, 2^66755640 is an apocalyptic number.

66755640 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 66755640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116492040).

66755640 is an abundant number, since it is smaller than the sum of its proper divisors (166228440).

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

66755640 is a wasteful number, since it uses less digits than its factorization.

66755640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11381 (or 11370 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 39.

The square root of 66755640 is about 8170.4124742879. The cubic root of 66755640 is about 405.6604374458.

The spelling of 66755640 in words is "sixty-six million, seven hundred fifty-five thousand, six hundred forty".