16643813 has 4 divisors (see below), whose sum is σ = 16679040. Its totient is φ = 16608588.

The previous prime is 16643779. The next prime is 16643839. The reversal of 16643813 is 31834661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31834661 = 3637 ⋅8753.

It is a cyclic number.

It is not a de Polignac number, because 16643813 - 2¹² = 16639717 is a prime.

It is a super-2 number, since 2×16643813² = 554033022357938, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16643813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16643863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16895 + ... + 17852.

It is an arithmetic number, because the mean of its divisors is an integer number (4169760).

Almost surely, 2^16643813 is an apocalyptic number.

It is an amenable number.

16643813 is a deficient number, since it is larger than the sum of its proper divisors (35227).

16643813 is an equidigital number, since it uses as much as digits as its factorization.

16643813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35226.

The product of its digits is 10368, while the sum is 32.

The square root of 16643813 is about 4079.6829533678. The cubic root of 16643813 is about 255.3196708568.

The spelling of 16643813 in words is "sixteen million, six hundred forty-three thousand, eight hundred thirteen".