256641771 has 4 divisors (see below), whose sum is σ = 342189032. Its totient is φ = 171094512.

The previous prime is 256641769. The next prime is 256641773. The reversal of 256641771 is 177146652.

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

It is an interprime number because it is at equal distance from previous prime (256641769) and next prime (256641773).

It is not a de Polignac number, because 256641771 - 2¹ = 256641769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256641773) 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, 42773626 + ... + 42773631.

It is an arithmetic number, because the mean of its divisors is an integer number (85547258).

Almost surely, 2^256641771 is an apocalyptic number.

256641771 is a deficient number, since it is larger than the sum of its proper divisors (85547261).

256641771 is an equidigital number, since it uses as much as digits as its factorization.

256641771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85547260.

The product of its digits is 70560, while the sum is 39.

The square root of 256641771 is about 16020.0427902050. The cubic root of 256641771 is about 635.4905759114.

The spelling of 256641771 in words is "two hundred fifty-six million, six hundred forty-one thousand, seven hundred seventy-one".