21783120 has 160 divisors (see below), whose sum is σ = 75530880. Its totient is φ = 5160960.

The previous prime is 21783119. The next prime is 21783133. The reversal of 21783120 is 2138712.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77380 + ... + 77660.

It is an arithmetic number, because the mean of its divisors is an integer number (472068).

Almost surely, 2^21783120 is an apocalyptic number.

21783120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21783120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37765440).

21783120 is an abundant number, since it is smaller than the sum of its proper divisors (53747760).

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

21783120 is a wasteful number, since it uses less digits than its factorization.

21783120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333 (or 327 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21783120 is about 4667.2390125212. The cubic root of 21783120 is about 279.2801235822.

The spelling of 21783120 in words is "twenty-one million, seven hundred eighty-three thousand, one hundred twenty".