78930991 has 4 divisors (see below), whose sum is σ = 81477184. Its totient is φ = 76384800.

The previous prime is 78930989. The next prime is 78931003. The reversal of 78930991 is 19903987.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19903987 = 3673 ⋅5419.

It is a cyclic number.

It is not a de Polignac number, because 78930991 - 2¹ = 78930989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78930931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1273050 + ... + 1273111.

It is an arithmetic number, because the mean of its divisors is an integer number (20369296).

Almost surely, 2^78930991 is an apocalyptic number.

78930991 is a deficient number, since it is larger than the sum of its proper divisors (2546193).

78930991 is a wasteful number, since it uses less digits than its factorization.

78930991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2546192.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 78930991 is about 8884.3115096219. The cubic root of 78930991 is about 428.9590668088.

The spelling of 78930991 in words is "seventy-eight million, nine hundred thirty thousand, nine hundred ninety-one".