257241981 has 4 divisors (see below), whose sum is σ = 342989312. Its totient is φ = 171494652.

The previous prime is 257241979. The next prime is 257241989. The reversal of 257241981 is 189142752.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 257241981 - 2¹ = 257241979 is a prime.

It is a super-2 number, since 2×257241981² = 132346873577608722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257241989) 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, 42873661 + ... + 42873666.

It is an arithmetic number, because the mean of its divisors is an integer number (85747328).

Almost surely, 2^257241981 is an apocalyptic number.

It is an amenable number.

257241981 is a deficient number, since it is larger than the sum of its proper divisors (85747331).

257241981 is an equidigital number, since it uses as much as digits as its factorization.

257241981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85747330.

The product of its digits is 40320, while the sum is 39.

The square root of 257241981 is about 16038.7649462170. The cubic root of 257241981 is about 635.9855990371.

The spelling of 257241981 in words is "two hundred fifty-seven million, two hundred forty-one thousand, nine hundred eighty-one".