256936248561 has 4 divisors (see below), whose sum is σ = 342581664752. Its totient is φ = 171290832372.

The previous prime is 256936248559. The next prime is 256936248563. The reversal of 256936248561 is 165842639652.

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 an interprime number because it is at equal distance from previous prime (256936248559) and next prime (256936248563).

It is not a de Polignac number, because 256936248561 - 2¹ = 256936248559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256936248563) 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, 42822708091 + ... + 42822708096.

It is an arithmetic number, because the mean of its divisors is an integer number (85645416188).

Almost surely, 2^256936248561 is an apocalyptic number.

It is an amenable number.

256936248561 is a deficient number, since it is larger than the sum of its proper divisors (85645416191).

256936248561 is an equidigital number, since it uses as much as digits as its factorization.

256936248561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85645416190.

The product of its digits is 18662400, while the sum is 57.

The spelling of 256936248561 in words is "two hundred fifty-six billion, nine hundred thirty-six million, two hundred forty-eight thousand, five hundred sixty-one".