781123313 has 2 divisors, whose sum is σ = 781123314. Its totient is φ = 781123312.

The previous prime is 781123297. The next prime is 781123339. The reversal of 781123313 is 313321187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 756690064 + 24433249 = 27508^2 + 4943^2 .

It is an emirp because it is prime and its reverse (313321187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 781123313 - 2⁴ = 781123297 is a prime.

It is a super-2 number, since 2×781123313² = 1220307260224191938, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (781123813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390561656 + 390561657.

It is an arithmetic number, because the mean of its divisors is an integer number (390561657).

Almost surely, 2^781123313 is an apocalyptic number.

It is an amenable number.

781123313 is a deficient number, since it is larger than the sum of its proper divisors (1).

781123313 is an equidigital number, since it uses as much as digits as its factorization.

781123313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 781123313 is about 27948.5833809157. The cubic root of 781123313 is about 920.9580886197.

The spelling of 781123313 in words is "seven hundred eighty-one million, one hundred twenty-three thousand, three hundred thirteen".