16643881 has 8 divisors (see below), whose sum is σ = 17772480. Its totient is φ = 15549072.

The previous prime is 16643863. The next prime is 16643897. The reversal of 16643881 is 18834661.

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

It is a cyclic number.

It is not a de Polignac number, because 16643881 - 2⁵ = 16643849 is a prime.

It is a super-2 number, since 2×16643881² = 554037549484322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16643881.

It is not an unprimeable number, because it can be changed into a prime (16643281) 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, 7426 + ... + 9403.

It is an arithmetic number, because the mean of its divisors is an integer number (2221560).

Almost surely, 2^16643881 is an apocalyptic number.

It is an amenable number.

16643881 is a deficient number, since it is larger than the sum of its proper divisors (1128599).

16643881 is a wasteful number, since it uses less digits than its factorization.

16643881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16895.

The product of its digits is 27648, while the sum is 37.

The square root of 16643881 is about 4079.6912873403. The cubic root of 16643881 is about 255.3200185679.

The spelling of 16643881 in words is "sixteen million, six hundred forty-three thousand, eight hundred eighty-one".