257139945 has 24 divisors (see below), whose sum is σ = 451820616. Its totient is φ = 135260928.

The previous prime is 257139929. The next prime is 257139979. The reversal of 257139945 is 549931752.

It is a happy number.

257139945 is a `hidden beast` number, since 2 + 571 + 39 + 9 + 45 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 114921 + 257025024 = 339^2 + 16032^2 .

It is not a de Polignac number, because 257139945 - 2⁴ = 257139929 is a prime.

It is a super-2 number, since 2×257139945² = 132241902629206050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 257139945.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35854 + ... + 42423.

It is an arithmetic number, because the mean of its divisors is an integer number (18825859).

Almost surely, 2^257139945 is an apocalyptic number.

It is an amenable number.

257139945 is a deficient number, since it is larger than the sum of its proper divisors (194680671).

257139945 is a wasteful number, since it uses less digits than its factorization.

257139945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78361 (or 78358 counting only the distinct ones).

The product of its digits is 340200, while the sum is 45.

The square root of 257139945 is about 16035.5837124814. The cubic root of 257139945 is about 635.9014992227.

The spelling of 257139945 in words is "two hundred fifty-seven million, one hundred thirty-nine thousand, nine hundred forty-five".