21543087 has 8 divisors (see below), whose sum is σ = 28988080. Its totient is φ = 14230080.

The previous prime is 21543077. The next prime is 21543091. The reversal of 21543087 is 78034512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21543087 - 2⁷ = 21542959 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 (21543007) 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 7 ways as a sum of consecutive naturals, for example, 32614 + ... + 33267.

It is an arithmetic number, because the mean of its divisors is an integer number (3623510).

Almost surely, 2^21543087 is an apocalyptic number.

21543087 is a deficient number, since it is larger than the sum of its proper divisors (7444993).

21543087 is a wasteful number, since it uses less digits than its factorization.

21543087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65993.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 21543087 is about 4641.4531129809. The cubic root of 21543087 is about 278.2505160355.

Adding to 21543087 its reverse (78034512), we get a palindrome (99577599).

The spelling of 21543087 in words is "twenty-one million, five hundred forty-three thousand, eighty-seven".