21533943 has 8 divisors (see below), whose sum is σ = 29323008. Its totient is φ = 14050424.

The previous prime is 21533929. The next prime is 21533947. The reversal of 21533943 is 34933512.

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 21533943 - 2⁹ = 21533431 is a prime.

It is a super-2 number, since 2×21533943² = 927421402254498, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21533943.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21533947) 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, 76221 + ... + 76502.

It is an arithmetic number, because the mean of its divisors is an integer number (3665376).

Almost surely, 2^21533943 is an apocalyptic number.

21533943 is a deficient number, since it is larger than the sum of its proper divisors (7789065).

21533943 is a wasteful number, since it uses less digits than its factorization.

21533943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152773.

The product of its digits is 9720, while the sum is 30.

The square root of 21533943 is about 4640.4679720907. The cubic root of 21533943 is about 278.2111424957.

The spelling of 21533943 in words is "twenty-one million, five hundred thirty-three thousand, nine hundred forty-three".