66331639 has 16 divisors (see below), whose sum is σ = 75294720. Its totient is φ = 57900960.

The previous prime is 66331627. The next prime is 66331663. The reversal of 66331639 is 93613366.

It is a cyclic number.

It is not a de Polignac number, because 66331639 - 2⁷ = 66331511 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66331598 and 66331607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66331619) 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 15 ways as a sum of consecutive naturals, for example, 31122 + ... + 33184.

It is an arithmetic number, because the mean of its divisors is an integer number (4705920).

Almost surely, 2^66331639 is an apocalyptic number.

66331639 is a deficient number, since it is larger than the sum of its proper divisors (8963081).

66331639 is a wasteful number, since it uses less digits than its factorization.

66331639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2190.

The product of its digits is 52488, while the sum is 37.

The square root of 66331639 is about 8144.4237979123. The cubic root of 66331639 is about 404.7997567235.

It can be divided in two parts, 66 and 331639, that added together give a triangular number (331705 = T₈₁₄).

The spelling of 66331639 in words is "sixty-six million, three hundred thirty-one thousand, six hundred thirty-nine".