21546009 has 12 divisors (see below), whose sum is σ = 32475456. Its totient is φ = 13739352.

The previous prime is 21546001. The next prime is 21546011. The reversal of 21546009 is 90064512.

21546009 is a `hidden beast` number, since 2 + 1 + 54 + 600 + 9 = 666.

It is not a de Polignac number, because 21546009 - 2³ = 21546001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21546001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 51837 + ... + 52250.

It is an arithmetic number, because the mean of its divisors is an integer number (2706288).

Almost surely, 2^21546009 is an apocalyptic number.

It is an amenable number.

21546009 is a deficient number, since it is larger than the sum of its proper divisors (10929447).

21546009 is a wasteful number, since it uses less digits than its factorization.

21546009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104116 (or 104113 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21546009 is about 4641.7678744203. The cubic root of 21546009 is about 278.2630956510.

The spelling of 21546009 in words is "twenty-one million, five hundred forty-six thousand, nine".