21879543 has 32 divisors (see below), whose sum is σ = 35458560. Its totient is φ = 11733120.

The previous prime is 21879523. The next prime is 21879551. The reversal of 21879543 is 34597812.

It is not a de Polignac number, because 21879543 - 2⁶ = 21879479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21879523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22048 + ... + 23018.

It is an arithmetic number, because the mean of its divisors is an integer number (1108080).

Almost surely, 2^21879543 is an apocalyptic number.

21879543 is a deficient number, since it is larger than the sum of its proper divisors (13579017).

21879543 is a wasteful number, since it uses less digits than its factorization.

21879543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1047.

The product of its digits is 60480, while the sum is 39.

The square root of 21879543 is about 4677.5573753830. The cubic root of 21879543 is about 279.6915949568.

It can be divided in two parts, 21879 and 543, that added together give a palindrome (22422).

The spelling of 21879543 in words is "twenty-one million, eight hundred seventy-nine thousand, five hundred forty-three".