21546321 has 16 divisors (see below), whose sum is σ = 29640000. Its totient is φ = 13912128.

The previous prime is 21546313. The next prime is 21546347. The reversal of 21546321 is 12364512.

It is not a de Polignac number, because 21546321 - 2³ = 21546313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21546291 and 21546300.

It is not an unprimeable number, because it can be changed into a prime (21546221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42930 + ... + 43428.

It is an arithmetic number, because the mean of its divisors is an integer number (1852500).

Almost surely, 2^21546321 is an apocalyptic number.

It is an amenable number.

21546321 is a deficient number, since it is larger than the sum of its proper divisors (8093679).

21546321 is a wasteful number, since it uses less digits than its factorization.

21546321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928.

The product of its digits is 1440, while the sum is 24.

The square root of 21546321 is about 4641.8014821834. The cubic root of 21546321 is about 278.2644387871.

The spelling of 21546321 in words is "twenty-one million, five hundred forty-six thousand, three hundred twenty-one".