78690939 has 4 divisors (see below), whose sum is σ = 104921256. Its totient is φ = 52460624.

The previous prime is 78690919. The next prime is 78690967. The reversal of 78690939 is 93909687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93909687 = 3 ⋅31303229.

It is a cyclic number.

It is not a de Polignac number, because 78690939 - 2¹¹ = 78688891 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78690891 and 78690900.

It is not an unprimeable number, because it can be changed into a prime (78690919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13115154 + ... + 13115159.

It is an arithmetic number, because the mean of its divisors is an integer number (26230314).

Almost surely, 2^78690939 is an apocalyptic number.

78690939 is a deficient number, since it is larger than the sum of its proper divisors (26230317).

78690939 is a wasteful number, since it uses less digits than its factorization.

78690939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26230316.

The product of its (nonzero) digits is 734832, while the sum is 51.

The square root of 78690939 is about 8870.7913401229. The cubic root of 78690939 is about 428.5237623019.

The spelling of 78690939 in words is "seventy-eight million, six hundred ninety thousand, nine hundred thirty-nine".