257820139 has 4 divisors (see below), whose sum is σ = 271389640. Its totient is φ = 244250640.

The previous prime is 257820109. The next prime is 257820187. The reversal of 257820139 is 931028752.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 257820139 - 2¹³ = 257811947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 257820098 and 257820107.

It is not an unprimeable number, because it can be changed into a prime (257820109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6784722 + ... + 6784759.

It is an arithmetic number, because the mean of its divisors is an integer number (67847410).

Almost surely, 2^257820139 is an apocalyptic number.

257820139 is a deficient number, since it is larger than the sum of its proper divisors (13569501).

257820139 is a wasteful number, since it uses less digits than its factorization.

257820139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13569500.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 257820139 is about 16056.7785997067. The cubic root of 257820139 is about 636.4617072163.

The spelling of 257820139 in words is "two hundred fifty-seven million, eight hundred twenty thousand, one hundred thirty-nine".