21984012 has 18 divisors (see below), whose sum is σ = 55570788. Its totient is φ = 7327992.

The previous prime is 21983999. The next prime is 21984073. The reversal of 21984012 is 21048912.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21984012² = 966593567232288, which contains 22 as substring.

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 5 ways as a sum of consecutive naturals, for example, 305298 + ... + 305369.

It is an arithmetic number, because the mean of its divisors is an integer number (3087266).

Almost surely, 2^21984012 is an apocalyptic number.

It is an amenable number.

21984012 is an abundant number, since it is smaller than the sum of its proper divisors (33586776).

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

21984012 is a wasteful number, since it uses less digits than its factorization.

21984012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610677 (or 610672 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 21984012 is about 4688.7111235392. The cubic root of 21984012 is about 280.1360393361.

The spelling of 21984012 in words is "twenty-one million, nine hundred eighty-four thousand, twelve".