13878042781 has 4 divisors (see below), whose sum is σ = 13889263132. Its totient is φ = 13866822432.

The previous prime is 13878042779. The next prime is 13878042793. The reversal of 13878042781 is 18724087831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18724087831 = 149 ⋅125665019.

It can be written as a sum of positive squares in 2 ways, for example, as 12173591556 + 1704451225 = 110334^2 + 41285^2 .

It is a cyclic number.

It is not a de Polignac number, because 13878042781 - 2¹ = 13878042779 is a prime.

It is a super-2 number, since 2×13878042781² (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 (13878045781) 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, 5608320 + ... + 5610793.

It is an arithmetic number, because the mean of its divisors is an integer number (3472315783).

Almost surely, 2^13878042781 is an apocalyptic number.

It is an amenable number.

13878042781 is a deficient number, since it is larger than the sum of its proper divisors (11220351).

13878042781 is a wasteful number, since it uses less digits than its factorization.

13878042781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11220350.

The product of its (nonzero) digits is 602112, while the sum is 49.

The spelling of 13878042781 in words is "thirteen billion, eight hundred seventy-eight million, forty-two thousand, seven hundred eighty-one".