20543543 has 4 divisors (see below), whose sum is σ = 20588568. Its totient is φ = 20498520.

The previous prime is 20543539. The next prime is 20543569. The reversal of 20543543 is 34534502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34534502 = 2 ⋅17267251.

It is a cyclic number.

It is not a de Polignac number, because 20543543 - 2² = 20543539 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 (20543573) 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, 21821 + ... + 22742.

It is an arithmetic number, because the mean of its divisors is an integer number (5147142).

Almost surely, 2^20543543 is an apocalyptic number.

20543543 is a deficient number, since it is larger than the sum of its proper divisors (45025).

20543543 is an equidigital number, since it uses as much as digits as its factorization.

20543543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45024.

The product of its (nonzero) digits is 7200, while the sum is 26.

The square root of 20543543 is about 4532.4985383340. The cubic root of 20543543 is about 273.8788202670.

The spelling of 20543543 in words is "twenty million, five hundred forty-three thousand, five hundred forty-three".