257720540 has 96 divisors (see below), whose sum is σ = 693149184. Its totient is φ = 78140160.

The previous prime is 257720539. The next prime is 257720549. The reversal of 257720540 is 45027752.

257720540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 257720497 and 257720506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257720549) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54719 + ... + 59241.

It is an arithmetic number, because the mean of its divisors is an integer number (7220304).

Almost surely, 2^257720540 is an apocalyptic number.

257720540 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 257720540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (346574592).

257720540 is an abundant number, since it is smaller than the sum of its proper divisors (435428644).

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

257720540 is a wasteful number, since it uses less digits than its factorization.

257720540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4587 (or 4585 counting only the distinct ones).

The product of its (nonzero) digits is 19600, while the sum is 32.

The square root of 257720540 is about 16053.6768374102. The cubic root of 257720540 is about 636.3797390730.

The spelling of 257720540 in words is "two hundred fifty-seven million, seven hundred twenty thousand, five hundred forty".