20171225 has 12 divisors (see below), whose sum is σ = 25545984. Its totient is φ = 15792720.

The previous prime is 20171219. The next prime is 20171233. The reversal of 20171225 is 52217102.

It is not a de Polignac number, because 20171225 - 2¹⁸ = 19909081 is a prime.

It is a Duffinian number.

It is a zygodrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 20171197 and 20171206.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7409 + ... + 9758.

It is an arithmetic number, because the mean of its divisors is an integer number (2128832).

Almost surely, 2^20171225 is an apocalyptic number.

20171225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20171225 is a deficient number, since it is larger than the sum of its proper divisors (5374759).

20171225 is a wasteful number, since it uses less digits than its factorization.

20171225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17224 (or 17219 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 20171225 is about 4491.2386932783. The cubic root of 20171225 is about 272.2141884497.

Adding to 20171225 its reverse (52217102), we get a palindrome (72388327).

The spelling of 20171225 in words is "twenty million, one hundred seventy-one thousand, two hundred twenty-five".