21481533 has 24 divisors (see below), whose sum is σ = 32853600. Its totient is φ = 13487904.

The previous prime is 21481531. The next prime is 21481549. The reversal of 21481533 is 33518412.

It is a happy number.

It is not a de Polignac number, because 21481533 - 2¹ = 21481531 is a prime.

It is a super-2 number, since 2×21481533² = 922912520060178, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21481497 and 21481506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21481531) 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 23 ways as a sum of consecutive naturals, for example, 45766 + ... + 46232.

It is an arithmetic number, because the mean of its divisors is an integer number (1368900).

Almost surely, 2^21481533 is an apocalyptic number.

It is an amenable number.

21481533 is a deficient number, since it is larger than the sum of its proper divisors (11372067).

21481533 is a wasteful number, since it uses less digits than its factorization.

21481533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 761 (or 758 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 21481533 is about 4634.8174721342. The cubic root of 21481533 is about 277.9852527415.

Adding to 21481533 its reverse (33518412), we get a palindrome (54999945).

The spelling of 21481533 in words is "twenty-one million, four hundred eighty-one thousand, five hundred thirty-three".