21481543 has 8 divisors (see below), whose sum is σ = 22230656. Its totient is φ = 20736000.

The previous prime is 21481531. The next prime is 21481549. The reversal of 21481543 is 34518412.

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 21481543 - 2¹³ = 21473351 is a prime.

It is a super-2 number, since 2×21481543² = 922913379321698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21481549) 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, 18055 + ... + 19207.

It is an arithmetic number, because the mean of its divisors is an integer number (2778832).

Almost surely, 2^21481543 is an apocalyptic number.

21481543 is a deficient number, since it is larger than the sum of its proper divisors (749113).

21481543 is a wasteful number, since it uses less digits than its factorization.

21481543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1785.

The product of its digits is 3840, while the sum is 28.

The square root of 21481543 is about 4634.8185509252. The cubic root of 21481543 is about 277.9852958770.

Adding to 21481543 its reverse (34518412), we get a palindrome (55999955).

The spelling of 21481543 in words is "twenty-one million, four hundred eighty-one thousand, five hundred forty-three".