78393789 has 6 divisors (see below), whose sum is σ = 113235486. Its totient is φ = 52262520.

The previous prime is 78393779. The next prime is 78393793. The reversal of 78393789 is 98739387.

It can be written as a sum of positive squares in only one way, i.e., 78322500 + 71289 = 8850^2 + 267^2 .

It is not a de Polignac number, because 78393789 - 2⁸ = 78393533 is a prime.

It is a super-2 number, since 2×78393789² = 12291172307553042, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78393719) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4355202 + ... + 4355219.

It is an arithmetic number, because the mean of its divisors is an integer number (18872581).

Almost surely, 2^78393789 is an apocalyptic number.

It is an amenable number.

78393789 is a deficient number, since it is larger than the sum of its proper divisors (34841697).

78393789 is a wasteful number, since it uses less digits than its factorization.

78393789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8710427 (or 8710424 counting only the distinct ones).

The product of its digits is 2286144, while the sum is 54.

The square root of 78393789 is about 8854.0267110507. The cubic root of 78393789 is about 427.9836897299.

It can be divided in two parts, 7839378 and 9, that added together give a palindrome (7839387).

The spelling of 78393789 in words is "seventy-eight million, three hundred ninety-three thousand, seven hundred eighty-nine".