3878161681 has 4 divisors (see below), whose sum is σ = 3941738164. Its totient is φ = 3814585200.

The previous prime is 3878161667. The next prime is 3878161691. The reversal of 3878161681 is 1861618783.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1861618783 = 3049 ⋅610567.

It can be written as a sum of positive squares in 2 ways, for example, as 589712656 + 3288449025 = 24284^2 + 57345^2 .

It is a cyclic number.

It is not a de Polignac number, because 3878161681 - 2¹⁵ = 3878128913 is a prime.

It is a super-2 number, since 2×3878161681² = 30080276047953491522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3878161631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31788150 + ... + 31788271.

It is an arithmetic number, because the mean of its divisors is an integer number (985434541).

Almost surely, 2^3878161681 is an apocalyptic number.

It is an amenable number.

3878161681 is a deficient number, since it is larger than the sum of its proper divisors (63576483).

3878161681 is an equidigital number, since it uses as much as digits as its factorization.

3878161681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63576482.

The product of its digits is 387072, while the sum is 49.

The square root of 3878161681 is about 62274.8880448612. Note that the first 3 decimals coincide. The cubic root of 3878161681 is about 1571.1173947335.

The spelling of 3878161681 in words is "three billion, eight hundred seventy-eight million, one hundred sixty-one thousand, six hundred eighty-one".