1005139991 has 2 divisors, whose sum is σ = 1005139992. Its totient is φ = 1005139990.

The previous prime is 1005139987. The next prime is 1005139999. The reversal of 1005139991 is 1999315001.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1999315001) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1005139991 - 2² = 1005139987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1005139999) 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, 502569995 + 502569996.

It is an arithmetic number, because the mean of its divisors is an integer number (502569996).

Almost surely, 2^1005139991 is an apocalyptic number.

1005139991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1005139991 is an equidigital number, since it uses as much as digits as its factorization.

1005139991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10935, while the sum is 38.

The square root of 1005139991 is about 31703.9428305061. The cubic root of 1005139991 is about 1001.7104031864.

The spelling of 1005139991 in words is "one billion, five million, one hundred thirty-nine thousand, nine hundred ninety-one".