66717640 has 32 divisors (see below), whose sum is σ = 163762560. Its totient is φ = 24260800.

The previous prime is 66717601. The next prime is 66717643. The reversal of 66717640 is 4671766.

It is a self number, because there is not a number n which added to its sum of digits gives 66717640.

It is not an unprimeable number, because it can be changed into a prime (66717643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75376 + ... + 76255.

It is an arithmetic number, because the mean of its divisors is an integer number (5117580).

Almost surely, 2^66717640 is an apocalyptic number.

It is an amenable number.

66717640 is an abundant number, since it is smaller than the sum of its proper divisors (97044920).

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

66717640 is a wasteful number, since it uses less digits than its factorization.

66717640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151653 (or 151649 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 37.

The square root of 66717640 is about 8168.0866792658. The cubic root of 66717640 is about 405.5834500805.

The spelling of 66717640 in words is "sixty-six million, seven hundred seventeen thousand, six hundred forty".