66667889 has 4 divisors (see below), whose sum is σ = 66737520. Its totient is φ = 66598260.

The previous prime is 66667877. The next prime is 66667919. The reversal of 66667889 is 98876666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66667889 - 2⁸ = 66667633 is a prime.

It is a Duffinian number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66667819) 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, 33359 + ... + 35300.

It is an arithmetic number, because the mean of its divisors is an integer number (16684380).

Almost surely, 2^66667889 is an apocalyptic number.

It is an amenable number.

66667889 is a deficient number, since it is larger than the sum of its proper divisors (69631).

66667889 is an equidigital number, since it uses as much as digits as its factorization.

66667889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69630.

The product of its digits is 5225472, while the sum is 56.

The square root of 66667889 is about 8165.0406612582. The cubic root of 66667889 is about 405.4826111825.

The spelling of 66667889 in words is "sixty-six million, six hundred sixty-seven thousand, eight hundred eighty-nine".