66639493 has 8 divisors (see below), whose sum is σ = 67485312. Its totient is φ = 65798016.

The previous prime is 66639457. The next prime is 66639509. The reversal of 66639493 is 39493666.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66639493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66639413) 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, 38421 + ... + 40117.

It is an arithmetic number, because the mean of its divisors is an integer number (8435664).

Almost surely, 2^66639493 is an apocalyptic number.

It is an amenable number.

66639493 is a deficient number, since it is larger than the sum of its proper divisors (845819).

66639493 is a wasteful number, since it uses less digits than its factorization.

66639493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2171.

The product of its digits is 629856, while the sum is 46.

The square root of 66639493 is about 8163.3015992305. The cubic root of 66639493 is about 405.4250336414.

The spelling of 66639493 in words is "sixty-six million, six hundred thirty-nine thousand, four hundred ninety-three".