21543534 has 12 divisors (see below), whose sum is σ = 46677696. Its totient is φ = 7181172.

The previous prime is 21543527. The next prime is 21543551. The reversal of 21543534 is 43534512.

It is a junction number, because it is equal to n+sod(n) for n = 21543498 and 21543507.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 598414 + ... + 598449.

It is an arithmetic number, because the mean of its divisors is an integer number (3889808).

Almost surely, 2^21543534 is an apocalyptic number.

21543534 is an abundant number, since it is smaller than the sum of its proper divisors (25134162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21543534 is a wasteful number, since it uses less digits than its factorization.

21543534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1196871 (or 1196868 counting only the distinct ones).

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

The square root of 21543534 is about 4641.5012657544. The cubic root of 21543534 is about 278.2524405062.

The spelling of 21543534 in words is "twenty-one million, five hundred forty-three thousand, five hundred thirty-four".