21543485 has 4 divisors (see below), whose sum is σ = 25852188. Its totient is φ = 17234784.

The previous prime is 21543461. The next prime is 21543499. The reversal of 21543485 is 58434512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12020089 + 9523396 = 3467^2 + 3086^2 .

It is a cyclic number.

It is not a de Polignac number, because 21543485 - 2⁸ = 21543229 is a prime.

It is a Duffinian number.

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 3 ways as a sum of consecutive naturals, for example, 2154344 + ... + 2154353.

It is an arithmetic number, because the mean of its divisors is an integer number (6463047).

Almost surely, 2^21543485 is an apocalyptic number.

It is an amenable number.

21543485 is a deficient number, since it is larger than the sum of its proper divisors (4308703).

21543485 is an equidigital number, since it uses as much as digits as its factorization.

21543485 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4308702.

The product of its digits is 19200, while the sum is 32.

The square root of 21543485 is about 4641.4959872869. The cubic root of 21543485 is about 278.2522295477.

Adding to 21543485 its reverse (58434512), we get a palindrome (79977997).

The spelling of 21543485 in words is "twenty-one million, five hundred forty-three thousand, four hundred eighty-five".