66650640 has 160 divisors (see below), whose sum is σ = 239151360. Its totient is φ = 15040512.

The previous prime is 66650629. The next prime is 66650681. The reversal of 66650640 is 4605666.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 162756 + ... + 163164.

It is an arithmetic number, because the mean of its divisors is an integer number (1494696).

Almost surely, 2^66650640 is an apocalyptic number.

66650640 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 66650640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119575680).

66650640 is an abundant number, since it is smaller than the sum of its proper divisors (172500720).

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

66650640 is a wasteful number, since it uses less digits than its factorization.

66650640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 529 (or 523 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 66650640 is about 8163.9843213960. The cubic root of 66650640 is about 405.4476379595.

The spelling of 66650640 in words is "sixty-six million, six hundred fifty thousand, six hundred forty".