25218220 has 12 divisors (see below), whose sum is σ = 52958304. Its totient is φ = 10087280.

The previous prime is 25218199. The next prime is 25218223. The reversal of 25218220 is 2281252.

It is a junction number, because it is equal to n+sod(n) for n = 25218191 and 25218200.

It is not an unprimeable number, because it can be changed into a prime (25218223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 630436 + ... + 630475.

It is an arithmetic number, because the mean of its divisors is an integer number (4413192).

Almost surely, 2^25218220 is an apocalyptic number.

25218220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25218220 is an abundant number, since it is smaller than the sum of its proper divisors (27740084).

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

25218220 is a wasteful number, since it uses less digits than its factorization.

25218220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260920 (or 1260918 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 25218220 is about 5021.7745867372. The cubic root of 25218220 is about 293.2500825503.

Adding to 25218220 its reverse (2281252), we get a palindrome (27499472).

The spelling of 25218220 in words is "twenty-five million, two hundred eighteen thousand, two hundred twenty".