66788889 has 8 divisors (see below), whose sum is σ = 89140032. Its totient is φ = 44481840.

The previous prime is 66788881. The next prime is 66788947. The reversal of 66788889 is 98888766.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66788889 - 2³ = 66788881 is a prime.

It is a Curzon number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66788881) 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, 7309 + ... + 13674.

It is an arithmetic number, because the mean of its divisors is an integer number (11142504).

Almost surely, 2^66788889 is an apocalyptic number.

It is an amenable number.

66788889 is a deficient number, since it is larger than the sum of its proper divisors (22351143).

66788889 is a wasteful number, since it uses less digits than its factorization.

66788889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22047.

The product of its digits is 9289728, while the sum is 60.

The square root of 66788889 is about 8172.4469407883. The cubic root of 66788889 is about 405.7277754026.

The spelling of 66788889 in words is "sixty-six million, seven hundred eighty-eight thousand, eight hundred eighty-nine".