21755543 has 8 divisors (see below), whose sum is σ = 22374576. Its totient is φ = 21140800.

The previous prime is 21755527. The next prime is 21755579. The reversal of 21755543 is 34555712.

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

It is a cyclic number.

It is not a de Polignac number, because 21755543 - 2⁴ = 21755527 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 (21755143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11108 + ... + 12918.

It is an arithmetic number, because the mean of its divisors is an integer number (2796822).

Almost surely, 2^21755543 is an apocalyptic number.

21755543 is a deficient number, since it is larger than the sum of its proper divisors (619033).

21755543 is a wasteful number, since it uses less digits than its factorization.

21755543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2145.

The product of its digits is 21000, while the sum is 32.

The square root of 21755543 is about 4664.2837606647. The cubic root of 21755543 is about 279.1622194386.

The spelling of 21755543 in words is "twenty-one million, seven hundred fifty-five thousand, five hundred forty-three".