257815540 has 48 divisors (see below), whose sum is σ = 574659792. Its totient is φ = 96823296.

The previous prime is 257815517. The next prime is 257815543. The reversal of 257815540 is 45518752.

It can be written as a sum of positive squares in 8 ways, for example, as 6022116 + 251793424 = 2454^2 + 15868^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 257815540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257815543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 207802 + ... + 209038.

It is an arithmetic number, because the mean of its divisors is an integer number (11972079).

Almost surely, 2^257815540 is an apocalyptic number.

257815540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 257815540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (287329896).

257815540 is an abundant number, since it is smaller than the sum of its proper divisors (316844252).

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

257815540 is a wasteful number, since it uses less digits than its factorization.

257815540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1876 (or 1874 counting only the distinct ones).

The product of its (nonzero) digits is 56000, while the sum is 37.

The square root of 257815540 is about 16056.6353885240. The cubic root of 257815540 is about 636.4579227889.

The spelling of 257815540 in words is "two hundred fifty-seven million, eight hundred fifteen thousand, five hundred forty".