78999966 has 36 divisors (see below), whose sum is σ = 176904936. Its totient is φ = 25478280.

The previous prime is 78999961. The next prime is 78999979. The reversal of 78999966 is 66999987.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78999961) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 15015 + ... + 19581.

It is an arithmetic number, because the mean of its divisors is an integer number (4914026).

Almost surely, 2^78999966 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78999966, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88452468).

78999966 is an abundant number, since it is smaller than the sum of its proper divisors (97904970).

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

78999966 is a wasteful number, since it uses less digits than its factorization.

78999966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4637 (or 4603 counting only the distinct ones).

The product of its digits is 13226976, while the sum is 63.

The square root of 78999966 is about 8888.1925046660. The cubic root of 78999966 is about 429.0839811463.

The spelling of 78999966 in words is "seventy-eight million, nine hundred ninety-nine thousand, nine hundred sixty-six".