245405 has 4 divisors (see below), whose sum is σ = 294492. Its totient is φ = 196320.

The previous prime is 245389. The next prime is 245407. The reversal of 245405 is 504542.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 106276 + 139129 = 326^2 + 373^2 .

It is not a de Polignac number, because 245405 - 2⁴ = 245389 is a prime.

It is a super-2 number, since 2×245405² = 120447228050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (245407) 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 3 ways as a sum of consecutive naturals, for example, 24536 + ... + 24545.

It is an arithmetic number, because the mean of its divisors is an integer number (73623).

2²⁴⁵⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

245405 is a deficient number, since it is larger than the sum of its proper divisors (49087).

245405 is an equidigital number, since it uses as much as digits as its factorization.

245405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49086.

The product of its (nonzero) digits is 800, while the sum is 20.

The square root of 245405 is about 495.3836896790. The cubic root of 245405 is about 62.6077076118.

Adding to 245405 its reverse (504542), we get a palindrome (749947).

It can be divided in two parts, 245 and 405, that multiplied together give a square (99225 = 315²).

The spelling of 245405 in words is "two hundred forty-five thousand, four hundred five".