20985825 has 48 divisors (see below), whose sum is σ = 40283136. Its totient is φ = 9441600.

The previous prime is 20985799. The next prime is 20985847. The reversal of 20985825 is 52858902.

It is not a de Polignac number, because 20985825 - 2⁵ = 20985793 is a prime.

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 47 ways as a sum of consecutive naturals, for example, 36994 + ... + 37556.

It is an arithmetic number, because the mean of its divisors is an integer number (839232).

Almost surely, 2^20985825 is an apocalyptic number.

20985825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20985825 is a deficient number, since it is larger than the sum of its proper divisors (19297311).

20985825 is a wasteful number, since it uses less digits than its factorization.

20985825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654 (or 649 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 39.

The square root of 20985825 is about 4581.0288145787. The cubic root of 20985825 is about 275.8303278718.

The spelling of 20985825 in words is "twenty million, nine hundred eighty-five thousand, eight hundred twenty-five".