66609500 has 48 divisors (see below), whose sum is σ = 147026880. Its totient is φ = 26360000.

The previous prime is 66609493. The next prime is 66609503. The reversal of 66609500 is 590666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66609503) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49841 + ... + 51159.

It is an arithmetic number, because the mean of its divisors is an integer number (3063060).

Almost surely, 2^66609500 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66609500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73513440).

66609500 is an abundant number, since it is smaller than the sum of its proper divisors (80417380).

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

66609500 is a wasteful number, since it uses less digits than its factorization.

66609500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1439 (or 1427 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 66609500 is about 8161.4643293958. The cubic root of 66609500 is about 405.3642001564.

The spelling of 66609500 in words is "sixty-six million, six hundred nine thousand, five hundred".