78634909 has 4 divisors (see below), whose sum is σ = 78659680. Its totient is φ = 78610140.

The previous prime is 78634903. The next prime is 78634931. The reversal of 78634909 is 90943687.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78634909 - 2¹¹ = 78632861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78634903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6777 + ... + 14254.

It is an arithmetic number, because the mean of its divisors is an integer number (19664920).

Almost surely, 2^78634909 is an apocalyptic number.

It is an amenable number.

78634909 is a deficient number, since it is larger than the sum of its proper divisors (24771).

78634909 is a wasteful number, since it uses less digits than its factorization.

78634909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24770.

The product of its (nonzero) digits is 326592, while the sum is 46.

The square root of 78634909 is about 8867.6326604117. The cubic root of 78634909 is about 428.4220314563.

The spelling of 78634909 in words is "seventy-eight million, six hundred thirty-four thousand, nine hundred nine".