78723913 has 4 divisors (see below), whose sum is σ = 78754500. Its totient is φ = 78693328.

The previous prime is 78723839. The next prime is 78723941. The reversal of 78723913 is 31932787.

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 9966649 + 68757264 = 3157^2 + 8292^2 .

It is a cyclic number.

It is not a de Polignac number, because 78723913 - 2⁹ = 78723401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78723613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11038 + ... + 16711.

It is an arithmetic number, because the mean of its divisors is an integer number (19688625).

Almost surely, 2^78723913 is an apocalyptic number.

It is an amenable number.

78723913 is a deficient number, since it is larger than the sum of its proper divisors (30587).

78723913 is a wasteful number, since it uses less digits than its factorization.

78723913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30586.

The product of its digits is 63504, while the sum is 40.

The square root of 78723913 is about 8872.6497169673. The cubic root of 78723913 is about 428.5836089607.

The spelling of 78723913 in words is "seventy-eight million, seven hundred twenty-three thousand, nine hundred thirteen".