242905 has 16 divisors (see below), whose sum is σ = 325584. Its totient is φ = 172800.

The previous prime is 242887. The next prime is 242911. The reversal of 242905 is 509242.

242905 = 348² + 349².

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 15376 + 227529 = 124^2 + 477^2 .

It is not a de Polignac number, because 242905 - 2⁵ = 242873 is a prime.

It is a Duffinian 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, 2355 + ... + 2455.

It is an arithmetic number, because the mean of its divisors is an integer number (20349).

2²⁴²⁹⁰⁵ is an apocalyptic number.

242905 is the 349-th centered square number.

It is an amenable number.

242905 is a deficient number, since it is larger than the sum of its proper divisors (82679).

242905 is a wasteful number, since it uses less digits than its factorization.

242905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 242905 is about 492.8539337370. The cubic root of 242905 is about 62.3943816167.

The spelling of 242905 in words is "two hundred forty-two thousand, nine hundred five".