78309938 has 24 divisors (see below), whose sum is σ = 139230252. Its totient is φ = 32925984.

The previous prime is 78309929. The next prime is 78309941. The reversal of 78309938 is 83990387.

It can be written as a sum of positive squares in 2 ways, for example, as 75463969 + 2845969 = 8687^2 + 1687^2 .

It is a super-2 number, since 2×78309938² = 12264892779127688, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78309892 and 78309901.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2345 + ... + 12732.

Almost surely, 2^78309938 is an apocalyptic number.

78309938 is a deficient number, since it is larger than the sum of its proper divisors (60920314).

78309938 is a wasteful number, since it uses less digits than its factorization.

78309938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15146 (or 15139 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 47.

The square root of 78309938 is about 8849.2902540260. The cubic root of 78309938 is about 427.8310430153.

The spelling of 78309938 in words is "seventy-eight million, three hundred nine thousand, nine hundred thirty-eight".