21549534 has 24 divisors (see below), whose sum is σ = 45491400. Its totient is φ = 6804432.

The previous prime is 21549529. The next prime is 21549571. The reversal of 21549534 is 43594512.

It is a junction number, because it is equal to n+sod(n) for n = 21549495 and 21549504.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 2809 + ... + 7140.

It is an arithmetic number, because the mean of its divisors is an integer number (1895475).

Almost surely, 2^21549534 is an apocalyptic number.

21549534 is an abundant number, since it is smaller than the sum of its proper divisors (23941866).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21549534 is a wasteful number, since it uses less digits than its factorization.

21549534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9992 (or 9973 counting only the distinct ones).

The product of its digits is 21600, while the sum is 33.

The square root of 21549534 is about 4642.1475633590. The cubic root of 21549534 is about 278.2782697516.

The spelling of 21549534 in words is "twenty-one million, five hundred forty-nine thousand, five hundred thirty-four".