251663240 has 64 divisors (see below), whose sum is σ = 625656960. Its totient is φ = 90618880.

The previous prime is 251663179. The next prime is 251663249. The reversal of 251663240 is 42366152.

It is not an unprimeable number, because it can be changed into a prime (251663249) 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, 7595 + ... + 23685.

It is an arithmetic number, because the mean of its divisors is an integer number (9775890).

Almost surely, 2^251663240 is an apocalyptic number.

251663240 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 251663240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (312828480).

251663240 is an abundant number, since it is smaller than the sum of its proper divisors (373993720).

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

251663240 is a wasteful number, since it uses less digits than its factorization.

251663240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16142 (or 16138 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 251663240 is about 15863.8973773786. The cubic root of 251663240 is about 631.3544722687.

It can be divided in two parts, 2516 and 63240, that added together give a palindrome (65756).

The spelling of 251663240 in words is "two hundred fifty-one million, six hundred sixty-three thousand, two hundred forty".