25641220 has 48 divisors (see below), whose sum is σ = 60782400. Its totient is φ = 9000320.

The previous prime is 25641211. The next prime is 25641221. The reversal of 25641220 is 2214652.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 25641191 and 25641200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25641221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4371 + ... + 8389.

It is an arithmetic number, because the mean of its divisors is an integer number (1266300).

Almost surely, 2^25641220 is an apocalyptic number.

25641220 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 25641220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30391200).

25641220 is an abundant number, since it is smaller than the sum of its proper divisors (35141180).

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

25641220 is a wasteful number, since it uses less digits than its factorization.

25641220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4068 (or 4066 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 25641220 is about 5063.7160267930. The cubic root of 25641220 is about 294.8806181697.

Adding to 25641220 its reverse (2214652), we get a palindrome (27855872).

The spelling of 25641220 in words is "twenty-five million, six hundred forty-one thousand, two hundred twenty".