20985804 has 120 divisors (see below), whose sum is σ = 66133760. Its totient is φ = 5668704.

The previous prime is 20985799. The next prime is 20985847. The reversal of 20985804 is 40858902.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 42849 + ... + 43335.

Almost surely, 2^20985804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20985804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33066880).

20985804 is an abundant number, since it is smaller than the sum of its proper divisors (45147956).

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

20985804 is a wasteful number, since it uses less digits than its factorization.

20985804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 529 (or 518 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 20985804 is about 4581.0265225165. The cubic root of 20985804 is about 275.8302358663.

The spelling of 20985804 in words is "twenty million, nine hundred eighty-five thousand, eight hundred four".