20878505 has 8 divisors (see below), whose sum is σ = 25200072. Its totient is φ = 16605568.

The previous prime is 20878477. The next prime is 20878513. The reversal of 20878505 is 50587802.

It can be written as a sum of positive squares in 4 ways, for example, as 7997584 + 12880921 = 2828^2 + 3589^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20878505 - 2⁶ = 20878441 is a prime.

It is a Duffinian number.

It is a Curzon number.

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 7 ways as a sum of consecutive naturals, for example, 11204 + ... + 12933.

It is an arithmetic number, because the mean of its divisors is an integer number (3150009).

Almost surely, 2^20878505 is an apocalyptic number.

It is an amenable number.

20878505 is a deficient number, since it is larger than the sum of its proper divisors (4321567).

20878505 is a wasteful number, since it uses less digits than its factorization.

20878505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24315.

The product of its (nonzero) digits is 22400, while the sum is 35.

The square root of 20878505 is about 4569.3002746591. The cubic root of 20878505 is about 275.3593319232.

The spelling of 20878505 in words is "twenty million, eight hundred seventy-eight thousand, five hundred five".