77785613 has 2 divisors, whose sum is σ = 77785614. Its totient is φ = 77785612.

The previous prime is 77785583. The next prime is 77785619. The reversal of 77785613 is 31658777.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47293129 + 30492484 = 6877^2 + 5522^2 .

It is a cyclic number.

It is not a de Polignac number, because 77785613 - 2⁶ = 77785549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77785619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38892806 + 38892807.

It is an arithmetic number, because the mean of its divisors is an integer number (38892807).

Almost surely, 2^77785613 is an apocalyptic number.

It is an amenable number.

77785613 is a deficient number, since it is larger than the sum of its proper divisors (1).

77785613 is an equidigital number, since it uses as much as digits as its factorization.

77785613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 246960, while the sum is 44.

The square root of 77785613 is about 8819.6152410408. The cubic root of 77785613 is about 426.8740549274.

The spelling of 77785613 in words is "seventy-seven million, seven hundred eighty-five thousand, six hundred thirteen".