78991649100 has 432 divisors, whose sum is σ = 305942640640. Its totient is φ = 16600204800.

The previous prime is 78991649089. The next prime is 78991649173. The reversal of 78991649100 is 194619987.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 22193121 + ... + 22196679.

Almost surely, 2^78991649100 is an apocalyptic number.

78991649100 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78991649100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152971320320).

78991649100 is an abundant number, since it is smaller than the sum of its proper divisors (226950991540).

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

78991649100 is a wasteful number, since it uses less digits than its factorization.

78991649100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3870 (or 3860 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 54.

The spelling of 78991649100 in words is "seventy-eight billion, nine hundred ninety-one million, six hundred forty-nine thousand, one hundred".