16638639 has 16 divisors (see below), whose sum is σ = 22692960. Its totient is φ = 10841600.

The previous prime is 16638619. The next prime is 16638647. The reversal of 16638639 is 93683661.

It is a cyclic number.

It is not a de Polignac number, because 16638639 - 2¹⁵ = 16605871 is a prime.

It is a super-3 number, since 3×16638639³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 16638639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16638619) 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, 26659 + ... + 27275.

It is an arithmetic number, because the mean of its divisors is an integer number (1418310).

Almost surely, 2^16638639 is an apocalyptic number.

16638639 is a deficient number, since it is larger than the sum of its proper divisors (6054321).

16638639 is a wasteful number, since it uses less digits than its factorization.

16638639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 810.

The product of its digits is 139968, while the sum is 42.

The square root of 16638639 is about 4079.0487861755. The cubic root of 16638639 is about 255.2932113573.

The spelling of 16638639 in words is "sixteen million, six hundred thirty-eight thousand, six hundred thirty-nine".