21481043 has 4 divisors (see below), whose sum is σ = 21609840. Its totient is φ = 21352248.

The previous prime is 21481003. The next prime is 21481049. The reversal of 21481043 is 34018412.

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 21481043 - 2¹² = 21476947 is a prime.

It is a super-2 number, since 2×21481043² = 922870416735698, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21481049) 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 3 ways as a sum of consecutive naturals, for example, 64148 + ... + 64481.

It is an arithmetic number, because the mean of its divisors is an integer number (5402460).

Almost surely, 2^21481043 is an apocalyptic number.

21481043 is a deficient number, since it is larger than the sum of its proper divisors (128797).

21481043 is a wasteful number, since it uses less digits than its factorization.

21481043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128796.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 21481043 is about 4634.7646110671. The cubic root of 21481043 is about 277.9831390840.

Adding to 21481043 its reverse (34018412), we get a palindrome (55499455).

The spelling of 21481043 in words is "twenty-one million, four hundred eighty-one thousand, forty-three".