256120646135 has 4 divisors (see below), whose sum is σ = 307344775368. Its totient is φ = 204896516904.

The previous prime is 256120646129. The next prime is 256120646147. The reversal of 256120646135 is 531646021652.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 256120646135 - 2¹² = 256120642039 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256120646092 and 256120646101.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25612064609 + ... + 25612064618.

It is an arithmetic number, because the mean of its divisors is an integer number (76836193842).

Almost surely, 2^256120646135 is an apocalyptic number.

256120646135 is a deficient number, since it is larger than the sum of its proper divisors (51224129233).

256120646135 is an equidigital number, since it uses as much as digits as its factorization.

256120646135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51224129232.

The product of its (nonzero) digits is 259200, while the sum is 41.

Adding to 256120646135 its reverse (531646021652), we get a palindrome (787766667787).

The spelling of 256120646135 in words is "two hundred fifty-six billion, one hundred twenty million, six hundred forty-six thousand, one hundred thirty-five".