20975543 has 4 divisors (see below), whose sum is σ = 20991120. Its totient is φ = 20959968.

The previous prime is 20975533. The next prime is 20975551. The reversal of 20975543 is 34557902.

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 20975543 - 2¹⁰ = 20974519 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 (20975533) 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, 5555 + ... + 8532.

It is an arithmetic number, because the mean of its divisors is an integer number (5247780).

Almost surely, 2^20975543 is an apocalyptic number.

20975543 is a deficient number, since it is larger than the sum of its proper divisors (15577).

20975543 is a wasteful number, since it uses less digits than its factorization.

20975543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15576.

The product of its (nonzero) digits is 37800, while the sum is 35.

The square root of 20975543 is about 4579.9064400924. The cubic root of 20975543 is about 275.7852728448.

The spelling of 20975543 in words is "twenty million, nine hundred seventy-five thousand, five hundred forty-three".