90010009991 has 4 divisors (see below), whose sum is σ = 98192738184. Its totient is φ = 81827281800.

The previous prime is 90010009981. The next prime is 90010009997. The reversal of 90010009991 is 19990001009.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 90010009991 - 2¹⁸ = 90009747847 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 (90010009997) 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 in 3 ways as a sum of consecutive naturals, for example, 4091364080 + ... + 4091364101.

It is an arithmetic number, because the mean of its divisors is an integer number (24548184546).

Almost surely, 2^90010009991 is an apocalyptic number.

90010009991 is a deficient number, since it is larger than the sum of its proper divisors (8182728193).

90010009991 is a wasteful number, since it uses less digits than its factorization.

90010009991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8182728192.

The product of its (nonzero) digits is 6561, while the sum is 38.

The spelling of 90010009991 in words is "ninety billion, ten million, nine thousand, nine hundred ninety-one".