25561220 has 24 divisors (see below), whose sum is σ = 53898264. Its totient is φ = 10182656.

The previous prime is 25561199. The next prime is 25561223. The reversal of 25561220 is 2216552.

It can be written as a sum of positive squares in 4 ways, for example, as 11303044 + 14258176 = 3362^2 + 3776^2 .

It is not an unprimeable number, because it can be changed into a prime (25561223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2654 + ... + 7626.

It is an arithmetic number, because the mean of its divisors is an integer number (2245761).

Almost surely, 2^25561220 is an apocalyptic number.

25561220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25561220 is an abundant number, since it is smaller than the sum of its proper divisors (28337044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25561220 is a wasteful number, since it uses less digits than its factorization.

25561220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5239 (or 5237 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 25561220 is about 5055.8105186013. The cubic root of 25561220 is about 294.5736251594.

Adding to 25561220 its reverse (2216552), we get a palindrome (27777772).

The spelling of 25561220 in words is "twenty-five million, five hundred sixty-one thousand, two hundred twenty".