19641 has 4 divisors (see below), whose sum is σ = 26192. Its totient is φ = 13092.

The previous prime is 19609. The next prime is 19661. The reversal of 19641 is 14691.

19641 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

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.

It is not a de Polignac number, because 19641 - 2⁵ = 19609 is a prime.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 7.

It is a nialpdrome in base 3.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 19641.

It is not an unprimeable number, because it can be changed into a prime (19661) 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, 3271 + ... + 3276.

It is an arithmetic number, because the mean of its divisors is an integer number (6548).

2¹⁹⁶⁴¹ is an apocalyptic number.

It is an amenable number.

19641 is a deficient number, since it is larger than the sum of its proper divisors (6551).

19641 is an equidigital number, since it uses as much as digits as its factorization.

19641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6550.

The product of its digits is 216, while the sum is 21.

The square root of 19641 is about 140.1463520753. The cubic root of 19641 is about 26.9807819346.

Subtracting from 19641 its reverse (14691), we obtain a triangular number (4950 = T₉₉).

The spelling of 19641 in words is "nineteen thousand, six hundred forty-one".