257282640 has 120 divisors (see below), whose sum is σ = 891990528. Its totient is φ = 66389760.

The previous prime is 257282633. The next prime is 257282647. The reversal of 257282640 is 46282752.

257282640 is a `hidden beast` number, since 2 + 5 + 7 + 2 + 8 + 2 + 640 = 666.

257282640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (257282633) and next prime (257282647).

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 257282595 and 257282604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257282647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16557 + ... + 28083.

Almost surely, 2^257282640 is an apocalyptic number.

257282640 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 257282640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (445995264).

257282640 is an abundant number, since it is smaller than the sum of its proper divisors (634707888).

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

257282640 is a wasteful number, since it uses less digits than its factorization.

257282640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11577 (or 11568 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 257282640 is about 16040.0324189199. The cubic root of 257282640 is about 636.0191046830.

The spelling of 257282640 in words is "two hundred fifty-seven million, two hundred eighty-two thousand, six hundred forty".