253440 has 120 divisors (see below), whose sum is σ = 957528. Its totient is φ = 61440.

The previous prime is 253439. The next prime is 253447. The reversal of 253440 is 44352.

253440 = T₅ + T₆ + ... + T₁₁₄.

253440 = 39² + 40² + ... + 93².

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 253440.

It is not an unprimeable number, because it can be changed into a prime (253447) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23035 + ... + 23045.

253440 is a Friedman number, since it can be written as 40^3*(4-5^(-2)), using all its digits and the basic arithmetic operations.

2²⁵³⁴⁴⁰ is an apocalyptic number.

253440 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 253440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (478764).

253440 is an abundant number, since it is smaller than the sum of its proper divisors (704088).

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

253440 is a wasteful number, since it uses less digits than its factorization.

253440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40 (or 21 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 18.

The square root of 253440 is about 503.4282471217. The cubic root of 253440 is about 63.2836791477.

253440 divided by its product of nonzero digits (480) gives a triangular number (528 = T₃₂).

Adding to 253440 its reverse (44352), we get a palindrome (297792).

The spelling of 253440 in words is "two hundred fifty-three thousand, four hundred forty".