99999999991806 has 16 divisors (see below), whose sum is σ = 200001187411200. Its totient is φ = 33333135426008.

The previous prime is 99999999991741. The next prime is 99999999991807. The reversal of 99999999991806 is 60819999999999.

It is a super-2 number, since 2×99999999991806² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 99999999991695 and 99999999991704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999999991807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48379476 + ... + 50404103.

It is an arithmetic number, because the mean of its divisors is an integer number (12500074213200).

Almost surely, 2^{99999999991806} is an apocalyptic number.

99999999991806 is an abundant number, since it is smaller than the sum of its proper divisors (100001187419394).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

99999999991806 is a wasteful number, since it uses less digits than its factorization.

99999999991806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98952303.

The product of its (nonzero) digits is 167365651248, while the sum is 105.

The spelling of 99999999991806 in words is "ninety-nine trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-one thousand, eight hundred six".