21546220 has 12 divisors (see below), whose sum is σ = 45247104. Its totient is φ = 8618480.

The previous prime is 21546211. The next prime is 21546221. The reversal of 21546220 is 2264512.

It is a junction number, because it is equal to n+sod(n) for n = 21546191 and 21546200.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 538636 + ... + 538675.

It is an arithmetic number, because the mean of its divisors is an integer number (3770592).

Almost surely, 2^21546220 is an apocalyptic number.

21546220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21546220 is an abundant number, since it is smaller than the sum of its proper divisors (23700884).

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

21546220 is a wasteful number, since it uses less digits than its factorization.

21546220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1077320 (or 1077318 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21546220 is about 4641.7906027739. The cubic root of 21546220 is about 278.2640039912.

The spelling of 21546220 in words is "twenty-one million, five hundred forty-six thousand, two hundred twenty".