66639289 has 8 divisors (see below), whose sum is σ = 70993440. Its totient is φ = 62369856.

The previous prime is 66639281. The next prime is 66639299. The reversal of 66639289 is 98293666.

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

It is not a de Polignac number, because 66639289 - 2³ = 66639281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66639281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19552 + ... + 22705.

It is an arithmetic number, because the mean of its divisors is an integer number (8874180).

Almost surely, 2^66639289 is an apocalyptic number.

It is an amenable number.

66639289 is a deficient number, since it is larger than the sum of its proper divisors (4354151).

66639289 is a wasteful number, since it uses less digits than its factorization.

66639289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42359.

The product of its digits is 839808, while the sum is 49.

The square root of 66639289 is about 8163.2891042765. The cubic root of 66639289 is about 405.4246199388.

The spelling of 66639289 in words is "sixty-six million, six hundred thirty-nine thousand, two hundred eighty-nine".