257213305 has 4 divisors (see below), whose sum is σ = 308655972. Its totient is φ = 205770640.

The previous prime is 257213303. The next prime is 257213321. The reversal of 257213305 is 503312752.

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 107101801 + 150111504 = 10349^2 + 12252^2 .

It is not a de Polignac number, because 257213305 - 2¹ = 257213303 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257213303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25721326 + ... + 25721335.

It is an arithmetic number, because the mean of its divisors is an integer number (77163993).

Almost surely, 2^257213305 is an apocalyptic number.

It is an amenable number.

257213305 is a deficient number, since it is larger than the sum of its proper divisors (51442667).

257213305 is an equidigital number, since it uses as much as digits as its factorization.

257213305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51442666.

The product of its (nonzero) digits is 6300, while the sum is 28.

The square root of 257213305 is about 16037.8709621945. The cubic root of 257213305 is about 635.9619660351.

The spelling of 257213305 in words is "two hundred fifty-seven million, two hundred thirteen thousand, three hundred five".