78722779 has 4 divisors (see below), whose sum is σ = 78740640. Its totient is φ = 78704920.

The previous prime is 78722773. The next prime is 78722821. The reversal of 78722779 is 97722787.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 78722779 - 2¹¹ = 78720731 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78722773) 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, 2949 + ... + 12889.

It is an arithmetic number, because the mean of its divisors is an integer number (19685160).

Almost surely, 2^78722779 is an apocalyptic number.

78722779 is a deficient number, since it is larger than the sum of its proper divisors (17861).

78722779 is an equidigital number, since it uses as much as digits as its factorization.

78722779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17860.

The product of its digits is 691488, while the sum is 49.

The square root of 78722779 is about 8872.5858124901. The cubic root of 78722779 is about 428.5815510678.

The spelling of 78722779 in words is "seventy-eight million, seven hundred twenty-two thousand, seven hundred seventy-nine".