78991038 has 144 divisors (see below), whose sum is σ = 215115264. Its totient is φ = 21636720.

The previous prime is 78991013. The next prime is 78991093. The reversal of 78991038 is 83019987.

It is a junction number, because it is equal to n+sod(n) for n = 78990984 and 78991002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 738181 + ... + 738287.

It is an arithmetic number, because the mean of its divisors is an integer number (1493856).

Almost surely, 2^78991038 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78991038, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107557632).

78991038 is an abundant number, since it is smaller than the sum of its proper divisors (136124226).

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

78991038 is a wasteful number, since it uses less digits than its factorization.

78991038 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 78991038 is about 8887.6902511282. The cubic root of 78991038 is about 429.0678165566.

The spelling of 78991038 in words is "seventy-eight million, nine hundred ninety-one thousand, thirty-eight".