1991141819 has 2 divisors, whose sum is σ = 1991141820. Its totient is φ = 1991141818.

The previous prime is 1991141807. The next prime is 1991141837. The reversal of 1991141819 is 9181411991.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1991141819 is a prime.

It is a super-2 number, since 2×1991141819² = 7929291486741257522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1991141819.

It is not a weakly prime, because it can be changed into another prime (1991141839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995570909 + 995570910.

It is an arithmetic number, because the mean of its divisors is an integer number (995570910).

Almost surely, 2^1991141819 is an apocalyptic number.

1991141819 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991141819 is an equidigital number, since it uses as much as digits as its factorization.

1991141819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 44.

The square root of 1991141819 is about 44622.2121706219. The cubic root of 1991141819 is about 1258.0581954807.

The spelling of 1991141819 in words is "one billion, nine hundred ninety-one million, one hundred forty-one thousand, eight hundred nineteen".