99209900991 has 4 divisors (see below), whose sum is σ = 132279867992. Its totient is φ = 66139933992.

The previous prime is 99209900989. The next prime is 99209901017. The reversal of 99209900991 is 19900990299.

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

It is not a de Polignac number, because 99209900991 - 2¹ = 99209900989 is a prime.

It is a super-4 number, since 4×99209900991⁴ (a number of 45 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99209900981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16534983496 + ... + 16534983501.

It is an arithmetic number, because the mean of its divisors is an integer number (33069966998).

Almost surely, 2^99209900991 is an apocalyptic number.

99209900991 is a deficient number, since it is larger than the sum of its proper divisors (33069967001).

99209900991 is a wasteful number, since it uses less digits than its factorization.

99209900991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33069967000.

The product of its (nonzero) digits is 1062882, while the sum is 57.

The spelling of 99209900991 in words is "ninety-nine billion, two hundred nine million, nine hundred thousand, nine hundred ninety-one".