251008220 has 12 divisors (see below), whose sum is σ = 527117304. Its totient is φ = 100403280.

The previous prime is 251008211. The next prime is 251008301. The reversal of 251008220 is 22800152.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 12550411 = 251008220 / (2 + 5 + 1 + 0 + 0 + 8 + 2 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 251008192 and 251008201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6275186 + ... + 6275225.

It is an arithmetic number, because the mean of its divisors is an integer number (43926442).

Almost surely, 2^251008220 is an apocalyptic number.

251008220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251008220 is an abundant number, since it is smaller than the sum of its proper divisors (276109084).

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

251008220 is a wasteful number, since it uses less digits than its factorization.

251008220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12550420 (or 12550418 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 251008220 is about 15843.2389365306. The cubic root of 251008220 is about 630.8062408080.

Adding to 251008220 its reverse (22800152), we get a palindrome (273808372).

The spelling of 251008220 in words is "two hundred fifty-one million, eight thousand, two hundred twenty".