20782440 has 128 divisors (see below), whose sum is σ = 79200000. Its totient is φ = 4748544.

The previous prime is 20782417. The next prime is 20782469. The reversal of 20782440 is 4428702.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 6186 + ... + 8934.

It is an arithmetic number, because the mean of its divisors is an integer number (618750).

Almost surely, 2^20782440 is an apocalyptic number.

20782440 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 20782440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39600000).

20782440 is an abundant number, since it is smaller than the sum of its proper divisors (58417560).

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

20782440 is a wasteful number, since it uses less digits than its factorization.

20782440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2776 (or 2766 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 27.

The square root of 20782440 is about 4558.7761515565. The cubic root of 20782440 is about 274.9363599293.

The spelling of 20782440 in words is "twenty million, seven hundred eighty-two thousand, four hundred forty".