253561 has 16 divisors (see below), whose sum is σ = 328320. Its totient is φ = 190080.

The previous prime is 253553. The next prime is 253567. The reversal of 253561 is 165352.

253561 = 18² + 19² + ... + 91².

It is a happy number.

It is not a de Polignac number, because 253561 - 2³ = 253553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (253567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2805 + ... + 2893.

It is an arithmetic number, because the mean of its divisors is an integer number (20520).

2²⁵³⁵⁶¹ is an apocalyptic number.

It is an amenable number.

253561 is a deficient number, since it is larger than the sum of its proper divisors (74759).

253561 is a wasteful number, since it uses less digits than its factorization.

253561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144.

The product of its digits is 900, while the sum is 22.

The square root of 253561 is about 503.5484087950. The cubic root of 253561 is about 63.2937487327.

Subtracting from 253561 its reverse (165352), we obtain a square (88209 = 297²).

The spelling of 253561 in words is "two hundred fifty-three thousand, five hundred sixty-one".