78409687 has 4 divisors (see below), whose sum is σ = 78476176. Its totient is φ = 78343200.

The previous prime is 78409663. The next prime is 78409693. The reversal of 78409687 is 78690487.

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

It is a cyclic number.

It is not a de Polignac number, because 78409687 - 2¹¹ = 78407639 is a prime.

It is a super-2 number, since 2×78409687² = 12296158030875938, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78409687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78409607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31443 + ... + 33844.

It is an arithmetic number, because the mean of its divisors is an integer number (19619044).

Almost surely, 2^78409687 is an apocalyptic number.

78409687 is a deficient number, since it is larger than the sum of its proper divisors (66489).

78409687 is a wasteful number, since it uses less digits than its factorization.

78409687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66488.

The product of its (nonzero) digits is 677376, while the sum is 49.

The square root of 78409687 is about 8854.9244491413. The cubic root of 78409687 is about 428.0126189979.

The spelling of 78409687 in words is "seventy-eight million, four hundred nine thousand, six hundred eighty-seven".