1991441819 has 2 divisors, whose sum is σ = 1991441820. Its totient is φ = 1991441818.

The previous prime is 1991441797. The next prime is 1991441831. The reversal of 1991441819 is 9181441991.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1991441819 is a prime.

It is a super-2 number, since 2×1991441819² = 7931681036924057522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1991441849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995720909 + 995720910.

It is an arithmetic number, because the mean of its divisors is an integer number (995720910).

Almost surely, 2^1991441819 is an apocalyptic number.

1991441819 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991441819 is an equidigital number, since it uses as much as digits as its factorization.

1991441819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 47.

The square root of 1991441819 is about 44625.5735985545. The cubic root of 1991441819 is about 1258.1213750597.

The spelling of 1991441819 in words is "one billion, nine hundred ninety-one million, four hundred forty-one thousand, eight hundred nineteen".