257809540 has 12 divisors (see below), whose sum is σ = 541400076. Its totient is φ = 103123808.

The previous prime is 257809511. The next prime is 257809567. The reversal of 257809540 is 45908752.

It can be written as a sum of positive squares in 2 ways, for example, as 126202756 + 131606784 = 11234^2 + 11472^2 .

It is a junction number, because it is equal to n+sod(n) for n = 257809493 and 257809502.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6445219 + ... + 6445258.

It is an arithmetic number, because the mean of its divisors is an integer number (45116673).

Almost surely, 2^257809540 is an apocalyptic number.

257809540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

257809540 is an abundant number, since it is smaller than the sum of its proper divisors (283590536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

257809540 is a wasteful number, since it uses less digits than its factorization.

257809540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12890486 (or 12890484 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 257809540 is about 16056.4485487919. The cubic root of 257809540 is about 636.4529854382.

The spelling of 257809540 in words is "two hundred fifty-seven million, eight hundred nine thousand, five hundred forty".