78191878 has 24 divisors (see below), whose sum is σ = 127174752. Its totient is φ = 36024912.

The previous prime is 78191873. The next prime is 78191899. The reversal of 78191878 is 87819187.

It is a super-2 number, since 2×78191878² = 12227939570333768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78191873) 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 11 ways as a sum of consecutive naturals, for example, 25251 + ... + 28177.

It is an arithmetic number, because the mean of its divisors is an integer number (5298948).

Almost surely, 2^78191878 is an apocalyptic number.

78191878 is a deficient number, since it is larger than the sum of its proper divisors (48982874).

78191878 is a wasteful number, since it uses less digits than its factorization.

78191878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3004 (or 2985 counting only the distinct ones).

The product of its digits is 225792, while the sum is 49.

The square root of 78191878 is about 8842.6171465240. The cubic root of 78191878 is about 427.6159356342.

The spelling of 78191878 in words is "seventy-eight million, one hundred ninety-one thousand, eight hundred seventy-eight".