20081543 has 4 divisors (see below), whose sum is σ = 20774040. Its totient is φ = 19389048.

The previous prime is 20081531. The next prime is 20081561. The reversal of 20081543 is 34518002.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20081543 - 2²⁰ = 19032967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 346205 + ... + 346262.

It is an arithmetic number, because the mean of its divisors is an integer number (5193510).

Almost surely, 2^20081543 is an apocalyptic number.

20081543 is a deficient number, since it is larger than the sum of its proper divisors (692497).

20081543 is an equidigital number, since it uses as much as digits as its factorization.

20081543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 692496.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 20081543 is about 4481.2434658251. The cubic root of 20081543 is about 271.8101643607.

Adding to 20081543 its reverse (34518002), we get a palindrome (54599545).

The spelling of 20081543 in words is "twenty million, eighty-one thousand, five hundred forty-three".