1019999081 has 2 divisors, whose sum is σ = 1019999082. Its totient is φ = 1019999080.

The previous prime is 1019999077. The next prime is 1019999119. The reversal of 1019999081 is 1809999101.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 993825625 + 26173456 = 31525^2 + 5116^2 .

It is an emirp because it is prime and its reverse (1809999101) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1019999081 - 2² = 1019999077 is a prime.

It is a super-2 number, since 2×1019999081² = 2080796250481689122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1019999051) 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, 509999540 + 509999541.

It is an arithmetic number, because the mean of its divisors is an integer number (509999541).

Almost surely, 2^1019999081 is an apocalyptic number.

It is an amenable number.

1019999081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1019999081 is an equidigital number, since it uses as much as digits as its factorization.

1019999081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 47.

The square root of 1019999081 is about 31937.4244578363. The cubic root of 1019999081 is about 1006.6224072442.

The spelling of 1019999081 in words is "one billion, nineteen million, nine hundred ninety-nine thousand, eighty-one".