20817625 has 8 divisors (see below), whose sum is σ = 25980552. Its totient is φ = 16654000.

The previous prime is 20817623. The next prime is 20817649. The reversal of 20817625 is 52671802.

It can be written as a sum of positive squares in 4 ways, for example, as 1272384 + 19545241 = 1128^2 + 4421^2 .

It is not a de Polignac number, because 20817625 - 2¹ = 20817623 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20817623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 83146 + ... + 83395.

It is an arithmetic number, because the mean of its divisors is an integer number (3247569).

Almost surely, 2^20817625 is an apocalyptic number.

20817625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20817625 is a deficient number, since it is larger than the sum of its proper divisors (5162927).

20817625 is an equidigital number, since it uses as much as digits as its factorization.

20817625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166556 (or 166546 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 20817625 is about 4562.6335596890. The cubic root of 20817625 is about 275.0914296540.

The spelling of 20817625 in words is "twenty million, eight hundred seventeen thousand, six hundred twenty-five".