257680642 has 4 divisors (see below), whose sum is σ = 386520966. Its totient is φ = 128840320.

The previous prime is 257680637. The next prime is 257680667. The reversal of 257680642 is 246086752.

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

It can be written as a sum of positive squares in only one way, i.e., 216707841 + 40972801 = 14721^2 + 6401^2 .

It is a junction number, because it is equal to n+sod(n) for n = 257680595 and 257680604.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64420159 + ... + 64420162.

Almost surely, 2^257680642 is an apocalyptic number.

257680642 is a deficient number, since it is larger than the sum of its proper divisors (128840324).

257680642 is a wasteful number, since it uses less digits than its factorization.

257680642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128840323.

The product of its (nonzero) digits is 161280, while the sum is 40.

The square root of 257680642 is about 16052.4341456366. The cubic root of 257680642 is about 636.3468978294.

The spelling of 257680642 in words is "two hundred fifty-seven million, six hundred eighty thousand, six hundred forty-two".