66638500 has 24 divisors (see below), whose sum is σ = 145539576. Its totient is φ = 26655200.

The previous prime is 66638497. The next prime is 66638513. The reversal of 66638500 is 583666.

It can be written as a sum of positive squares in 4 ways, for example, as 4260096 + 62378404 = 2064^2 + 7898^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66139 + ... + 67138.

It is an arithmetic number, because the mean of its divisors is an integer number (6064149).

Almost surely, 2^66638500 is an apocalyptic number.

It is an amenable number.

66638500 is an abundant number, since it is smaller than the sum of its proper divisors (78901076).

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

66638500 is a wasteful number, since it uses less digits than its factorization.

66638500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133296 (or 133284 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 66638500 is about 8163.2407780244. The cubic root of 66638500 is about 405.4230198753.

The spelling of 66638500 in words is "sixty-six million, six hundred thirty-eight thousand, five hundred".