1000000090991 has 8 divisors (see below), whose sum is σ = 1092173289984. Its totient is φ = 908037575320.

The previous prime is 1000000090939. The next prime is 1000000091047. The reversal of 1000000090991 is 1990900000001.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1000000090991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1000000090391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52660901 + ... + 52679886.

It is an arithmetic number, because the mean of its divisors is an integer number (136521661248).

Almost surely, 2^{1000000090991} is an apocalyptic number.

1000000090991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1000000090991 is a deficient number, since it is larger than the sum of its proper divisors (92173198993).

1000000090991 is a wasteful number, since it uses less digits than its factorization.

1000000090991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105341661.

The product of its (nonzero) digits is 729, while the sum is 29.

Adding to 1000000090991 its reverse (1990900000001), we get a palindrome (2990900090992).

The spelling of 1000000090991 in words is "one trillion, ninety thousand, nine hundred ninety-one".