1991010013 has 2 divisors, whose sum is σ = 1991010014. Its totient is φ = 1991010012.

The previous prime is 1991009987. The next prime is 1991010041. The reversal of 1991010013 is 3100101991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1980428004 + 10582009 = 44502^2 + 3253^2 .

It is a cyclic number.

It is not a de Polignac number, because 1991010013 - 2¹⁷ = 1990878941 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1991010013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1991010083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995505006 + 995505007.

It is an arithmetic number, because the mean of its divisors is an integer number (995505007).

Almost surely, 2^1991010013 is an apocalyptic number.

It is an amenable number.

1991010013 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991010013 is an equidigital number, since it uses as much as digits as its factorization.

1991010013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 243, while the sum is 25.

The square root of 1991010013 is about 44620.7352359864. The cubic root of 1991010013 is about 1258.0304353155.

The spelling of 1991010013 in words is "one billion, nine hundred ninety-one million, ten thousand, thirteen".