21864192 has 144 divisors (see below), whose sum is σ = 68678400. Its totient is φ = 6171648.

The previous prime is 21864187. The next prime is 21864209. The reversal of 21864192 is 29146812.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 263383 + ... + 263465.

Almost surely, 2^21864192 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21864192, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34339200).

21864192 is an abundant number, since it is smaller than the sum of its proper divisors (46814208).

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

21864192 is an frugal number, since it uses more digits than its factorization.

21864192 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 95 counting only the distinct ones).

The product of its digits is 6912, while the sum is 33.

The square root of 21864192 is about 4675.9161669132. The cubic root of 21864192 is about 279.6261677798.

The spelling of 21864192 in words is "twenty-one million, eight hundred sixty-four thousand, one hundred ninety-two".