78833991 has 4 divisors (see below), whose sum is σ = 105111992. Its totient is φ = 52555992.

The previous prime is 78833969. The next prime is 78833999. The reversal of 78833991 is 19933887.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 78833991 - 2⁵ = 78833959 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78833991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78833999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13138996 + ... + 13139001.

It is an arithmetic number, because the mean of its divisors is an integer number (26277998).

Almost surely, 2^78833991 is an apocalyptic number.

78833991 is a deficient number, since it is larger than the sum of its proper divisors (26278001).

78833991 is a wasteful number, since it uses less digits than its factorization.

78833991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26278000.

The product of its digits is 326592, while the sum is 48.

The square root of 78833991 is about 8878.8507702292. The cubic root of 78833991 is about 428.7832757566.

The spelling of 78833991 in words is "seventy-eight million, eight hundred thirty-three thousand, nine hundred ninety-one".