25531220 has 96 divisors (see below), whose sum is σ = 64350720. Its totient is φ = 8386560.

The previous prime is 25531217. The next prime is 25531241. The reversal of 25531220 is 2213552.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 25531192 and 25531201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 225884 + ... + 225996.

It is an arithmetic number, because the mean of its divisors is an integer number (670320).

Almost surely, 2^25531220 is an apocalyptic number.

25531220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25531220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32175360).

25531220 is an abundant number, since it is smaller than the sum of its proper divisors (38819500).

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

25531220 is a wasteful number, since it uses less digits than its factorization.

25531220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 25531220 is about 5052.8427642269. The cubic root of 25531220 is about 294.4583376486.

Adding to 25531220 its reverse (2213552), we get a palindrome (27744772).

It can be divided in two parts, 2553 and 1220, that added together give a palindrome (3773).

The spelling of 25531220 in words is "twenty-five million, five hundred thirty-one thousand, two hundred twenty".