66581888 has 32 divisors (see below), whose sum is σ = 135739560. Its totient is φ = 32514048.

The previous prime is 66581881. The next prime is 66581903. The reversal of 66581888 is 88818566.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66581881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545 + ... + 11552.

Almost surely, 2^66581888 is an apocalyptic number.

It is an amenable number.

66581888 is an abundant number, since it is smaller than the sum of its proper divisors (69157672).

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

66581888 is a wasteful number, since it uses less digits than its factorization.

66581888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12154 (or 12142 counting only the distinct ones).

The product of its digits is 737280, while the sum is 50.

The square root of 66581888 is about 8159.7725458495. The cubic root of 66581888 is about 405.3081798026.

The spelling of 66581888 in words is "sixty-six million, five hundred eighty-one thousand, eight hundred eighty-eight".