253021440 has 144 divisors (see below), whose sum is σ = 923626368. Its totient is φ = 57827328.

The previous prime is 253021427. The next prime is 253021451. The reversal of 253021440 is 44120352.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22174 + ... + 31586.

It is an arithmetic number, because the mean of its divisors is an integer number (6414072).

Almost surely, 2^253021440 is an apocalyptic number.

253021440 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 253021440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (461813184).

253021440 is an abundant number, since it is smaller than the sum of its proper divisors (670604928).

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

253021440 is an equidigital number, since it uses as much as digits as its factorization.

253021440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9444 (or 9430 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 253021440 is about 15906.6476669347. The cubic root of 253021440 is about 632.4882196663.

Adding to 253021440 its reverse (44120352), we get a palindrome (297141792).

The spelling of 253021440 in words is "two hundred fifty-three million, twenty-one thousand, four hundred forty".