77831813 has 2 divisors, whose sum is σ = 77831814. Its totient is φ = 77831812.

The previous prime is 77831783. The next prime is 77831861. The reversal of 77831813 is 31813877.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73239364 + 4592449 = 8558^2 + 2143^2 .

It is a cyclic number.

It is not a de Polignac number, because 77831813 - 2⁶ = 77831749 is a prime.

It is a super-2 number, since 2×77831813² = 12115582229733938, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77831713) 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 as a sum of consecutive naturals, namely, 38915906 + 38915907.

It is an arithmetic number, because the mean of its divisors is an integer number (38915907).

Almost surely, 2^77831813 is an apocalyptic number.

It is an amenable number.

77831813 is a deficient number, since it is larger than the sum of its proper divisors (1).

77831813 is an equidigital number, since it uses as much as digits as its factorization.

77831813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28224, while the sum is 38.

The square root of 77831813 is about 8822.2340141259. The cubic root of 77831813 is about 426.9585507503.

The spelling of 77831813 in words is "seventy-seven million, eight hundred thirty-one thousand, eight hundred thirteen".