4129781891 has 2 divisors, whose sum is σ = 4129781892. Its totient is φ = 4129781890.

The previous prime is 4129781869. The next prime is 4129781897. The reversal of 4129781891 is 1981879214.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 4129781891 - 2¹⁸ = 4129519747 is a prime.

It is not a weakly prime, because it can be changed into another prime (4129781897) 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 as a sum of consecutive naturals, namely, 2064890945 + 2064890946.

It is an arithmetic number, because the mean of its divisors is an integer number (2064890946).

Almost surely, 2^4129781891 is an apocalyptic number.

4129781891 is a deficient number, since it is larger than the sum of its proper divisors (1).

4129781891 is an equidigital number, since it uses as much as digits as its factorization.

4129781891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 290304, while the sum is 50.

The square root of 4129781891 is about 64263.3790817134. The cubic root of 4129781891 is about 1604.3866460681.

The spelling of 4129781891 in words is "four billion, one hundred twenty-nine million, seven hundred eighty-one thousand, eight hundred ninety-one".