20780040 has 64 divisors (see below), whose sum is σ = 65059200. Its totient is φ = 5299712.

The previous prime is 20780033. The next prime is 20780047. The reversal of 20780040 is 4008702.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20780033) and next prime (20780047).

It is a junction number, because it is equal to n+sod(n) for n = 20779989 and 20780016.

It is not an unprimeable number, because it can be changed into a prime (20780047) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1005 + ... + 6524.

It is an arithmetic number, because the mean of its divisors is an integer number (1016550).

Almost surely, 2^20780040 is an apocalyptic number.

20780040 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 20780040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32529600).

20780040 is an abundant number, since it is smaller than the sum of its proper divisors (44279160).

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

20780040 is a wasteful number, since it uses less digits than its factorization.

20780040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7566 (or 7562 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 20780040 is about 4558.5129154144. The cubic root of 20780040 is about 274.9257761117.

Adding to 20780040 its reverse (4008702), we get a palindrome (24788742).

The spelling of 20780040 in words is "twenty million, seven hundred eighty thousand, forty".