78205685 has 4 divisors (see below), whose sum is σ = 93846828. Its totient is φ = 62564544.

The previous prime is 78205669. The next prime is 78205693. The reversal of 78205685 is 58650287.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8031556 + 70174129 = 2834^2 + 8377^2 .

It is a cyclic number.

It is not a de Polignac number, because 78205685 - 2⁴ = 78205669 is a prime.

It is a super-2 number, since 2×78205685² = 12232258332638450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7820564 + ... + 7820573.

It is an arithmetic number, because the mean of its divisors is an integer number (23461707).

Almost surely, 2^78205685 is an apocalyptic number.

It is an amenable number.

78205685 is a deficient number, since it is larger than the sum of its proper divisors (15641143).

78205685 is a wasteful number, since it uses less digits than its factorization.

78205685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15641142.

The product of its (nonzero) digits is 134400, while the sum is 41.

The square root of 78205685 is about 8843.3978198428. The cubic root of 78205685 is about 427.6411034048.

The spelling of 78205685 in words is "seventy-eight million, two hundred five thousand, six hundred eighty-five".