21798784 has 32 divisors (see below), whose sum is σ = 49633200. Its totient is φ = 9341952.

The previous prime is 21798769. The next prime is 21798787. The reversal of 21798784 is 48789712.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21798787) 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, 11269 + ... + 13060.

Almost surely, 2^21798784 is an apocalyptic number.

It is an amenable number.

21798784 is an abundant number, since it is smaller than the sum of its proper divisors (27834416).

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

21798784 is an equidigital number, since it uses as much as digits as its factorization.

21798784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24350 (or 24338 counting only the distinct ones).

The product of its digits is 225792, while the sum is 46.

The square root of 21798784 is about 4668.9167908627. The cubic root of 21798784 is about 279.3470499559.

The spelling of 21798784 in words is "twenty-one million, seven hundred ninety-eight thousand, seven hundred eighty-four".