21544012 has 12 divisors (see below), whose sum is σ = 43088080. Its totient is φ = 9233136.

The previous prime is 21544009. The next prime is 21544021. The reversal of 21544012 is 21044512.

21544012 is an admirable number.

It is a super-2 number, since 2×21544012² = 928288906112288, which contains 22 as substring.

It is an unprimeable number.

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, 384687 + ... + 384742.

Almost surely, 2^21544012 is an apocalyptic number.

It is an amenable number.

21544012 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21544012 is a wasteful number, since it uses less digits than its factorization.

21544012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769440 (or 769438 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21544012 is about 4641.5527574293. The cubic root of 21544012 is about 278.2544984119.

Adding to 21544012 its reverse (21044512), we get a palindrome (42588524).

Subtracting from 21544012 its reverse (21044512), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 21544012 in words is "twenty-one million, five hundred forty-four thousand, twelve".