21543834 has 32 divisors (see below), whose sum is σ = 48847680. Its totient is φ = 6279552.

The previous prime is 21543829. The next prime is 21543859. The reversal of 21543834 is 43834512.

It is a Curzon 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 15 ways as a sum of consecutive naturals, for example, 5787 + ... + 8750.

It is an arithmetic number, because the mean of its divisors is an integer number (1526490).

Almost surely, 2^21543834 is an apocalyptic number.

21543834 is an abundant number, since it is smaller than the sum of its proper divisors (27303846).

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

21543834 is a wasteful number, since it uses less digits than its factorization.

21543834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14574.

The product of its digits is 11520, while the sum is 30.

The square root of 21543834 is about 4641.5335827720. The cubic root of 21543834 is about 278.2537320824.

The spelling of 21543834 in words is "twenty-one million, five hundred forty-three thousand, eight hundred thirty-four".