21534543 has 12 divisors (see below), whose sum is σ = 32742840. Its totient is φ = 13600656.

The previous prime is 21534533. The next prime is 21534547. The reversal of 21534543 is 34543512.

It is not a de Polignac number, because 21534543 - 2⁵ = 21534511 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21534547) 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 11 ways as a sum of consecutive naturals, for example, 62796 + ... + 63137.

It is an arithmetic number, because the mean of its divisors is an integer number (2728570).

Almost surely, 2^21534543 is an apocalyptic number.

21534543 is a deficient number, since it is larger than the sum of its proper divisors (11208297).

21534543 is a wasteful number, since it uses less digits than its factorization.

21534543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125958 (or 125955 counting only the distinct ones).

The product of its digits is 7200, while the sum is 27.

The square root of 21534543 is about 4640.5326202926. The cubic root of 21534543 is about 278.2137264029.

The spelling of 21534543 in words is "twenty-one million, five hundred thirty-four thousand, five hundred forty-three".