251397240 has 128 divisors (see below), whose sum is σ = 794041920. Its totient is φ = 63590400.

The previous prime is 251397233. The next prime is 251397247. The reversal of 251397240 is 42793152.

251397240 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (251397233) and next prime (251397247).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251397247) 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, 181350 + ... + 182730.

Almost surely, 2^251397240 is an apocalyptic number.

251397240 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 251397240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (397020960).

251397240 is an abundant number, since it is smaller than the sum of its proper divisors (542644680).

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

251397240 is a wasteful number, since it uses less digits than its factorization.

251397240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1473 (or 1469 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 251397240 is about 15855.5113446398. The cubic root of 251397240 is about 631.1319533534.

The spelling of 251397240 in words is "two hundred fifty-one million, three hundred ninety-seven thousand, two hundred forty".