78791819 has 4 divisors (see below), whose sum is σ = 79076544. Its totient is φ = 78507096.

The previous prime is 78791771. The next prime is 78791837. The reversal of 78791819 is 91819787.

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

It is a cyclic number.

It is not a de Polignac number, because 78791819 - 2¹⁶ = 78726283 is a prime.

It is a super-2 number, since 2×78791819² = 12416301482657522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78791899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141947 + ... + 142500.

It is an arithmetic number, because the mean of its divisors is an integer number (19769136).

Almost surely, 2^78791819 is an apocalyptic number.

78791819 is a deficient number, since it is larger than the sum of its proper divisors (284725).

78791819 is a wasteful number, since it uses less digits than its factorization.

78791819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284724.

The product of its digits is 254016, while the sum is 50.

The square root of 78791819 is about 8876.4755956404. The cubic root of 78791819 is about 428.7068033557.

The spelling of 78791819 in words is "seventy-eight million, seven hundred ninety-one thousand, eight hundred nineteen".