21543053 has 4 divisors (see below), whose sum is σ = 24620640. Its totient is φ = 18465468.

The previous prime is 21543031. The next prime is 21543077. The reversal of 21543053 is 35034512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21543053 - 2¹⁶ = 21477517 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 (21543013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1538783 + ... + 1538796.

It is an arithmetic number, because the mean of its divisors is an integer number (6155160).

Almost surely, 2^21543053 is an apocalyptic number.

It is an amenable number.

21543053 is a deficient number, since it is larger than the sum of its proper divisors (3077587).

21543053 is an equidigital number, since it uses as much as digits as its factorization.

21543053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3077586.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 21543053 is about 4641.4494503334. The cubic root of 21543053 is about 278.2503696541.

Adding to 21543053 its reverse (35034512), we get a palindrome (56577565).

The spelling of 21543053 in words is "twenty-one million, five hundred forty-three thousand, fifty-three".