20181225 has 24 divisors (see below), whose sum is σ = 34185312. Its totient is φ = 10499200.

The previous prime is 20181223. The next prime is 20181229. The reversal of 20181225 is 52218102.

It is a happy number.

It is not a de Polignac number, because 20181225 - 2¹ = 20181223 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20181223) 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, 207 + ... + 6356.

It is an arithmetic number, because the mean of its divisors is an integer number (1424388).

Almost surely, 2^20181225 is an apocalyptic number.

20181225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20181225 is a deficient number, since it is larger than the sum of its proper divisors (14004087).

20181225 is a wasteful number, since it uses less digits than its factorization.

20181225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6617 (or 6612 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 20181225 is about 4492.3518339507. The cubic root of 20181225 is about 272.2591649310.

Adding to 20181225 its reverse (52218102), we get a palindrome (72399327).

The spelling of 20181225 in words is "twenty million, one hundred eighty-one thousand, two hundred twenty-five".