13878386561 has 4 divisors (see below), whose sum is σ = 14945954772. Its totient is φ = 12810818352.

The previous prime is 13878386539. The next prime is 13878386563. The reversal of 13878386561 is 16568387831.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5143614961 + 8734771600 = 71719^2 + 93460^2 .

It is a cyclic number.

It is not a de Polignac number, because 13878386561 - 2²² = 13874192257 is a prime.

It is a super-2 number, since 2×13878386561² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 13878386497 and 13878386506.

It is not an unprimeable number, because it can be changed into a prime (13878386563) 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, 533784086 + ... + 533784111.

It is an arithmetic number, because the mean of its divisors is an integer number (3736488693).

Almost surely, 2^13878386561 is an apocalyptic number.

It is an amenable number.

13878386561 is a deficient number, since it is larger than the sum of its proper divisors (1067568211).

13878386561 is a wasteful number, since it uses less digits than its factorization.

13878386561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067568210.

The product of its digits is 5806080, while the sum is 56.

The spelling of 13878386561 in words is "thirteen billion, eight hundred seventy-eight million, three hundred eighty-six thousand, five hundred sixty-one".