3813778891 has 20 divisors (see below), whose sum is σ = 4195352072. Its totient is φ = 3466127808.

The previous prime is 3813778889. The next prime is 3813778897. The reversal of 3813778891 is 1988773183.

It is a happy number.

It is not a de Polignac number, because 3813778891 - 2¹ = 3813778889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3813778897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1912591 + ... + 1914583.

Almost surely, 2^3813778891 is an apocalyptic number.

3813778891 is a deficient number, since it is larger than the sum of its proper divisors (381573181).

3813778891 is an frugal number, since it uses more digits than its factorization.

3813778891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2112 (or 2073 counting only the distinct ones).

The product of its digits is 2032128, while the sum is 55.

The square root of 3813778891 is about 61755.8004644098. The cubic root of 3813778891 is about 1562.3746011876.

The spelling of 3813778891 in words is "three billion, eight hundred thirteen million, seven hundred seventy-eight thousand, eight hundred ninety-one".