20806825 has 24 divisors (see below), whose sum is σ = 28197848. Its totient is φ = 15137280.

The previous prime is 20806823. The next prime is 20806829. The reversal of 20806825 is 52860802.

It can be written as a sum of positive squares in 12 ways, for example, as 4910656 + 15896169 = 2216^2 + 3987^2 .

It is not a de Polignac number, because 20806825 - 2¹ = 20806823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806823) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23287 + ... + 24163.

Almost surely, 2^20806825 is an apocalyptic number.

20806825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20806825 is a deficient number, since it is larger than the sum of its proper divisors (7391023).

20806825 is a wasteful number, since it uses less digits than its factorization.

20806825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 973 (or 968 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 20806825 is about 4561.4498791503. The cubic root of 20806825 is about 275.0438497569.

The spelling of 20806825 in words is "twenty million, eight hundred six thousand, eight hundred twenty-five".