13256953781 has 4 divisors (see below), whose sum is σ = 13257555564. Its totient is φ = 13256352000.

The previous prime is 13256953769. The next prime is 13256953783. The reversal of 13256953781 is 18735965231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18735965231 = 61 ⋅307146971.

It can be written as a sum of positive squares in 2 ways, for example, as 7958424100 + 5298529681 = 89210^2 + 72791^2 .

It is a cyclic number.

It is not a de Polignac number, because 13256953781 - 2²⁶ = 13189844917 is a prime.

It is a super-2 number, since 2×13256953781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13256953783) 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, 266540 + ... + 312341.

It is an arithmetic number, because the mean of its divisors is an integer number (3314388891).

Almost surely, 2^13256953781 is an apocalyptic number.

It is an amenable number.

13256953781 is a deficient number, since it is larger than the sum of its proper divisors (601783).

13256953781 is an equidigital number, since it uses as much as digits as its factorization.

13256953781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 601782.

The product of its digits is 1360800, while the sum is 50.

The spelling of 13256953781 in words is "thirteen billion, two hundred fifty-six million, nine hundred fifty-three thousand, seven hundred eighty-one".