257715217 has 4 divisors (see below), whose sum is σ = 264000996. Its totient is φ = 251429440.

The previous prime is 257715151. The next prime is 257715229. The reversal of 257715217 is 712517752.

257715217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 128119761 + 129595456 = 11319^2 + 11384^2 .

It is a cyclic number.

It is not a de Polignac number, because 257715217 - 2⁷ = 257715089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257715247) 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, 3142828 + ... + 3142909.

It is an arithmetic number, because the mean of its divisors is an integer number (66000249).

Almost surely, 2^257715217 is an apocalyptic number.

It is an amenable number.

257715217 is a deficient number, since it is larger than the sum of its proper divisors (6285779).

257715217 is an equidigital number, since it uses as much as digits as its factorization.

257715217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6285778.

The product of its digits is 34300, while the sum is 37.

The square root of 257715217 is about 16053.5110489886. The cubic root of 257715217 is about 636.3753577476.

The spelling of 257715217 in words is "two hundred fifty-seven million, seven hundred fifteen thousand, two hundred seventeen".