20878985 has 16 divisors (see below), whose sum is σ = 26058240. Its totient is φ = 16040640.

The previous prime is 20878981. The next prime is 20878987. The reversal of 20878985 is 58987802.

It is not a de Polignac number, because 20878985 - 2² = 20878981 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20878981) 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 15 ways as a sum of consecutive naturals, for example, 44864 + ... + 45326.

It is an arithmetic number, because the mean of its divisors is an integer number (1628640).

Almost surely, 2^20878985 is an apocalyptic number.

It is an amenable number.

20878985 is a deficient number, since it is larger than the sum of its proper divisors (5179255).

20878985 is a wasteful number, since it uses less digits than its factorization.

20878985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 808.

The product of its (nonzero) digits is 322560, while the sum is 47.

The square root of 20878985 is about 4569.3527988108. The cubic root of 20878985 is about 275.3614420913.

The spelling of 20878985 in words is "twenty million, eight hundred seventy-eight thousand, nine hundred eighty-five".