19818541 has 4 divisors (see below), whose sum is σ = 19828732. Its totient is φ = 19808352.

The previous prime is 19818529. The next prime is 19818587. The reversal of 19818541 is 14581891.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 19616041 + 202500 = 4429^2 + 450^2 .

It is a cyclic number.

It is not a de Polignac number, because 19818541 - 2⁵ = 19818509 is a prime.

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 19818541.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19818511) 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, 1170 + ... + 6403.

It is an arithmetic number, because the mean of its divisors is an integer number (4957183).

Almost surely, 2^19818541 is an apocalyptic number.

It is an amenable number.

19818541 is a deficient number, since it is larger than the sum of its proper divisors (10191).

19818541 is an equidigital number, since it uses as much as digits as its factorization.

19818541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10190.

The product of its digits is 11520, while the sum is 37.

The square root of 19818541 is about 4451.8019946983. The cubic root of 19818541 is about 270.6183404854.

It can be divided in two parts, 19 and 818541, that added together give a triangular number (818560 = T₁₂₇₉).

The spelling of 19818541 in words is "nineteen million, eight hundred eighteen thousand, five hundred forty-one".