20783280 has 160 divisors (see below), whose sum is σ = 74995200. Its totient is φ = 4663296.

The previous prime is 20783267. The next prime is 20783291. The reversal of 20783280 is 8238702.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 149451 + ... + 149589.

It is an arithmetic number, because the mean of its divisors is an integer number (468720).

Almost surely, 2^20783280 is an apocalyptic number.

20783280 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 20783280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37497600).

20783280 is an abundant number, since it is smaller than the sum of its proper divisors (54211920).

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

20783280 is a wasteful number, since it uses less digits than its factorization.

20783280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 20783280 is about 4558.8682806153. The cubic root of 20783280 is about 274.9400640730.

The spelling of 20783280 in words is "twenty million, seven hundred eighty-three thousand, two hundred eighty".