16643631 has 4 divisors (see below), whose sum is σ = 22191512. Its totient is φ = 11095752.

The previous prime is 16643617. The next prime is 16643647. The reversal of 16643631 is 13634661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13634661 = 3 ⋅4544887.

It is not a de Polignac number, because 16643631 - 2⁶ = 16643567 is a prime.

It is a super-2 number, since 2×16643631² = 554020905728322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16643611) 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, 2773936 + ... + 2773941.

It is an arithmetic number, because the mean of its divisors is an integer number (5547878).

Almost surely, 2^16643631 is an apocalyptic number.

16643631 is a deficient number, since it is larger than the sum of its proper divisors (5547881).

16643631 is an equidigital number, since it uses as much as digits as its factorization.

16643631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5547880.

The product of its digits is 7776, while the sum is 30.

The square root of 16643631 is about 4079.6606476520. The cubic root of 16643631 is about 255.3187402137.

The spelling of 16643631 in words is "sixteen million, six hundred forty-three thousand, six hundred thirty-one".