251345231220 has 96 divisors (see below), whose sum is σ = 741227558400. Its totient is φ = 63461695104.

The previous prime is 251345231177. The next prime is 251345231227. The reversal of 251345231220 is 22132543152.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251345231227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1975491 + ... + 2098869.

It is an arithmetic number, because the mean of its divisors is an integer number (7721120400).

Almost surely, 2^251345231220 is an apocalyptic number.

251345231220 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 251345231220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (370613779200).

251345231220 is an abundant number, since it is smaller than the sum of its proper divisors (489882327180).

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

251345231220 is a wasteful number, since it uses less digits than its factorization.

251345231220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125197 (or 125195 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

Adding to 251345231220 its reverse (22132543152), we get a palindrome (273477774372).

The spelling of 251345231220 in words is "two hundred fifty-one billion, three hundred forty-five million, two hundred thirty-one thousand, two hundred twenty".