257447661 has 4 divisors (see below), whose sum is σ = 343263552. Its totient is φ = 171631772.

The previous prime is 257447639. The next prime is 257447731. The reversal of 257447661 is 166744752.

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 a cyclic number.

It is not a de Polignac number, because 257447661 - 2¹⁴ = 257431277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257447611) 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, 42907941 + ... + 42907946.

It is an arithmetic number, because the mean of its divisors is an integer number (85815888).

Almost surely, 2^257447661 is an apocalyptic number.

It is an amenable number.

257447661 is a deficient number, since it is larger than the sum of its proper divisors (85815891).

257447661 is an equidigital number, since it uses as much as digits as its factorization.

257447661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85815890.

The product of its digits is 282240, while the sum is 42.

The square root of 257447661 is about 16045.1756300765. The cubic root of 257447661 is about 636.1550564350.

The spelling of 257447661 in words is "two hundred fifty-seven million, four hundred forty-seven thousand, six hundred sixty-one".