78785791 has 4 divisors (see below), whose sum is σ = 90040912. Its totient is φ = 67530672.

The previous prime is 78785743. The next prime is 78785797. The reversal of 78785791 is 19758787.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19758787 = 127 ⋅155581.

It is a cyclic number.

It is not a de Polignac number, because 78785791 - 2⁹ = 78785279 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 (78785797) 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, 5627550 + ... + 5627563.

It is an arithmetic number, because the mean of its divisors is an integer number (22510228).

Almost surely, 2^78785791 is an apocalyptic number.

78785791 is a deficient number, since it is larger than the sum of its proper divisors (11255121).

78785791 is a wasteful number, since it uses less digits than its factorization.

78785791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11255120.

The product of its digits is 987840, while the sum is 52.

The square root of 78785791 is about 8876.1360399669. The cubic root of 78785791 is about 428.6958702811.

The spelling of 78785791 in words is "seventy-eight million, seven hundred eighty-five thousand, seven hundred ninety-one".