99999966 has 48 divisors (see below), whose sum is σ = 221339664. Its totient is φ = 30096000.

The previous prime is 99999959. The next prime is 99999971. The reversal of 99999966 is 66999999.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 99999897 and 99999906.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 131026 + ... + 131786.

It is an arithmetic number, because the mean of its divisors is an integer number (4611243).

Almost surely, 2^99999966 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99999966, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110669832).

99999966 is an abundant number, since it is smaller than the sum of its proper divisors (121339698).

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

99999966 is a wasteful number, since it uses less digits than its factorization.

99999966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 969 (or 958 counting only the distinct ones).

The product of its digits is 19131876, while the sum is 66.

The square root of 99999966 is about 9999.9982999999. The cubic root of 99999966 is about 464.1588307566.

99999966 divided by its sum of digits (66) gives a palindrome (1515151).

The spelling of 99999966 in words is "ninety-nine million, nine hundred ninety-nine thousand, nine hundred sixty-six".