257820137 has 4 divisors (see below), whose sum is σ = 258469956. Its totient is φ = 257170320.

The previous prime is 257820109. The next prime is 257820187. The reversal of 257820137 is 731028752.

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 62267881 + 195552256 = 7891^2 + 13984^2 .

It is a cyclic number.

It is not a de Polignac number, because 257820137 - 2²⁶ = 190711273 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 257820097 and 257820106.

It is not an unprimeable number, because it can be changed into a prime (257820187) 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, 324314 + ... + 325107.

It is an arithmetic number, because the mean of its divisors is an integer number (64617489).

Almost surely, 2^257820137 is an apocalyptic number.

It is an amenable number.

257820137 is a deficient number, since it is larger than the sum of its proper divisors (649819).

257820137 is an equidigital number, since it uses as much as digits as its factorization.

257820137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 649818.

The product of its (nonzero) digits is 23520, while the sum is 35.

The square root of 257820137 is about 16056.7785374277. The cubic root of 257820137 is about 636.4617055705.

Adding to 257820137 its reverse (731028752), we get a palindrome (988848889).

The spelling of 257820137 in words is "two hundred fifty-seven million, eight hundred twenty thousand, one hundred thirty-seven".