78771613 has 2 divisors, whose sum is σ = 78771614. Its totient is φ = 78771612.

The previous prime is 78771607. The next prime is 78771643. The reversal of 78771613 is 31617787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40170244 + 38601369 = 6338^2 + 6213^2 .

It is a cyclic number.

It is not a de Polignac number, because 78771613 - 2⁹ = 78771101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78771643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39385806 + 39385807.

It is an arithmetic number, because the mean of its divisors is an integer number (39385807).

Almost surely, 2^78771613 is an apocalyptic number.

It is an amenable number.

78771613 is a deficient number, since it is larger than the sum of its proper divisors (1).

78771613 is an equidigital number, since it uses as much as digits as its factorization.

78771613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 49392, while the sum is 40.

The square root of 78771613 is about 8875.3373457013. The cubic root of 78771613 is about 428.6701532298.

The spelling of 78771613 in words is "seventy-eight million, seven hundred seventy-one thousand, six hundred thirteen".