77813 has 2 divisors, whose sum is σ = 77814. Its totient is φ = 77812.

The previous prime is 77801. The next prime is 77839. The reversal of 77813 is 31877.

It is an a-pointer prime, because the next prime (77839) can be obtained adding 77813 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77284 + 529 = 278^2 + 23^2 .

It is a cyclic number.

It is not a de Polignac number, because 77813 - 2⁴ = 77797 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p₇₆₄₉ and since 77813 and 7649 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38906 + 38907.

It is an arithmetic number, because the mean of its divisors is an integer number (38907).

2⁷⁷⁸¹³ is an apocalyptic number.

It is an amenable number.

77813 is a deficient number, since it is larger than the sum of its proper divisors (1).

77813 is an equidigital number, since it uses as much as digits as its factorization.

77813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1176, while the sum is 26.

The square root of 77813 is about 278.9498162753. The cubic root of 77813 is about 42.6924147430.

The spelling of 77813 in words is "seventy-seven thousand, eight hundred thirteen".