21752543 has 4 divisors (see below), whose sum is σ = 21863160. Its totient is φ = 21641928.

The previous prime is 21752531. The next prime is 21752551. The reversal of 21752543 is 34525712.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21752543 - 2¹⁰ = 21751519 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 (21752573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55013 + ... + 55406.

It is an arithmetic number, because the mean of its divisors is an integer number (5465790).

Almost surely, 2^21752543 is an apocalyptic number.

21752543 is a deficient number, since it is larger than the sum of its proper divisors (110617).

21752543 is a wasteful number, since it uses less digits than its factorization.

21752543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110616.

The product of its digits is 8400, while the sum is 29.

The square root of 21752543 is about 4663.9621567933. The cubic root of 21752543 is about 279.1493870743.

The spelling of 21752543 in words is "twenty-one million, seven hundred fifty-two thousand, five hundred forty-three".