251220 has 48 divisors (see below), whose sum is σ = 725760.
Its totient is φ = 64896.
The previous prime is 251219. The next prime is 251221. The reversal of 251220 is 22152.
It is an interprime number because it is at equal distance from previous prime (251219) and next prime (251221).
It is a super-2 number, since 2×2512202 = 126222976800, which contains 22 as substring.
It is a Harshad number since it is a multiple of its sum of digits (12).
It is a nialpdrome in base 4.
It is a junction number, because it is equal to n+sod(n) for n = 251196 and 251205.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 251220.
It is not an unprimeable number, because it can be changed into a prime (251221) 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, 3141 + ... + 3219.
It is an arithmetic number, because the mean of its divisors is an integer number (15120).
2251220 is an apocalyptic number.
251220 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 251220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362880).
251220 is an abundant number, since it is smaller than the sum of its proper divisors (474540).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
251220 is a wasteful number, since it uses less digits than its factorization.
251220 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 144 (or 142 counting only the distinct ones).
The product of its (nonzero) digits is 40, while the sum is 12.
The square root of 251220 is about 501.2185152207.
The cubic root of 251220 is about 63.0983598336.
Adding to 251220 its reverse (22152), we get a palindrome (273372).
The spelling of 251220 in words is "two hundred fifty-one thousand, two hundred twenty".