78539985 has 12 divisors (see below), whose sum is σ = 136136052. Its totient is φ = 41887968.

The previous prime is 78539959. The next prime is 78540031. The reversal of 78539985 is 58993587.

It can be written as a sum of positive squares in 2 ways, for example, as 51322896 + 27217089 = 7164^2 + 5217^2 .

It is not a de Polignac number, because 78539985 - 2⁶ = 78539921 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 872622 + ... + 872711.

It is an arithmetic number, because the mean of its divisors is an integer number (11344671).

Almost surely, 2^78539985 is an apocalyptic number.

It is an amenable number.

78539985 is a deficient number, since it is larger than the sum of its proper divisors (57596067).

78539985 is a wasteful number, since it uses less digits than its factorization.

78539985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1745344 (or 1745341 counting only the distinct ones).

The product of its digits is 2721600, while the sum is 54.

The square root of 78539985 is about 8862.2787701584. The cubic root of 78539985 is about 428.2495723949.

It can be divided in two parts, 78539 and 985, that added together give a square (79524 = 282²).

The spelling of 78539985 in words is "seventy-eight million, five hundred thirty-nine thousand, nine hundred eighty-five".