78809992 has 8 divisors (see below), whose sum is σ = 147768750. Its totient is φ = 39404992.

The previous prime is 78809989. The next prime is 78809999. The reversal of 78809992 is 29990887.

It can be written as a sum of positive squares in only one way, i.e., 71808676 + 7001316 = 8474^2 + 2646^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×78809992² = 12422029678080128, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78809999) 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 as a sum of consecutive naturals, namely, 4925617 + ... + 4925632.

Almost surely, 2^78809992 is an apocalyptic number.

It is an amenable number.

78809992 is a deficient number, since it is larger than the sum of its proper divisors (68958758).

78809992 is a wasteful number, since it uses less digits than its factorization.

78809992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9851255 (or 9851251 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 52.

The square root of 78809992 is about 8877.4991974091. The cubic root of 78809992 is about 428.7397606261.

The spelling of 78809992 in words is "seventy-eight million, eight hundred nine thousand, nine hundred ninety-two".