256487641 has 4 divisors (see below), whose sum is σ = 259734400. Its totient is φ = 253240884.

The previous prime is 256487611. The next prime is 256487657. The reversal of 256487641 is 146784652.

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 256487641 - 2⁹ = 256487129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256487611) 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, 1623261 + ... + 1623418.

It is an arithmetic number, because the mean of its divisors is an integer number (64933600).

Almost surely, 2^256487641 is an apocalyptic number.

It is an amenable number.

256487641 is a deficient number, since it is larger than the sum of its proper divisors (3246759).

256487641 is an equidigital number, since it uses as much as digits as its factorization.

256487641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3246758.

The product of its digits is 322560, while the sum is 43.

The square root of 256487641 is about 16015.2315312642. The cubic root of 256487641 is about 635.3633326900.

The spelling of 256487641 in words is "two hundred fifty-six million, four hundred eighty-seven thousand, six hundred forty-one".