20878540 has 24 divisors (see below), whose sum is σ = 44502192. Its totient is φ = 8226240.

The previous prime is 20878537. The next prime is 20878541. The reversal of 20878540 is 4587802.

It is a junction number, because it is equal to n+sod(n) for n = 20878496 and 20878505.

It is not an unprimeable number, because it can be changed into a prime (20878541) 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 7 ways as a sum of consecutive naturals, for example, 6451 + ... + 9130.

It is an arithmetic number, because the mean of its divisors is an integer number (1854258).

Almost surely, 2^20878540 is an apocalyptic number.

20878540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20878540 is an abundant number, since it is smaller than the sum of its proper divisors (23623652).

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

20878540 is a wasteful number, since it uses less digits than its factorization.

20878540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15657 (or 15655 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 34.

The square root of 20878540 is about 4569.3041045656. The cubic root of 20878540 is about 275.3594857907.

The spelling of 20878540 in words is "twenty million, eight hundred seventy-eight thousand, five hundred forty".