381151891 has 2 divisors, whose sum is σ = 381151892. Its totient is φ = 381151890.

The previous prime is 381151889. The next prime is 381151909. The reversal of 381151891 is 198151183.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 381151891 - 2¹ = 381151889 is a prime.

Together with 381151889, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 381151891.

It is not a weakly prime, because it can be changed into another prime (381151801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 190575945 + 190575946.

It is an arithmetic number, because the mean of its divisors is an integer number (190575946).

Almost surely, 2^381151891 is an apocalyptic number.

381151891 is the 12348-th centered pentagonal number.

381151891 is a deficient number, since it is larger than the sum of its proper divisors (1).

381151891 is an equidigital number, since it uses as much as digits as its factorization.

381151891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 37.

The square root of 381151891 is about 19523.1117140685. Note that the first 3 decimals coincide. The cubic root of 381151891 is about 725.0467768471.

The spelling of 381151891 in words is "three hundred eighty-one million, one hundred fifty-one thousand, eight hundred ninety-one".