21783982 has 8 divisors (see below), whose sum is σ = 35646552. Its totient is φ = 9901800.

The previous prime is 21783947. The next prime is 21783989. The reversal of 21783982 is 28938712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21783989) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 495069 + ... + 495112.

It is an arithmetic number, because the mean of its divisors is an integer number (4455819).

Almost surely, 2^21783982 is an apocalyptic number.

21783982 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21783982 is a deficient number, since it is larger than the sum of its proper divisors (13862570).

21783982 is a wasteful number, since it uses less digits than its factorization.

21783982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990194.

The product of its digits is 48384, while the sum is 40.

The square root of 21783982 is about 4667.3313574247. The cubic root of 21783982 is about 279.2838074177.

The spelling of 21783982 in words is "twenty-one million, seven hundred eighty-three thousand, nine hundred eighty-two".