781346813 has 8 divisors (see below), whose sum is σ = 852978168. Its totient is φ = 711362304.

The previous prime is 781346711. The next prime is 781346837. The reversal of 781346813 is 318643187.

It can be written as a sum of positive squares in 4 ways, for example, as 62141689 + 719205124 = 7883^2 + 26818^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 781346813 - 2²⁰ = 780298237 is a prime.

It is a super-2 number, since 2×781346813² = 1221005684370513938, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781346873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 410720 + ... + 412617.

It is an arithmetic number, because the mean of its divisors is an integer number (106622271).

Almost surely, 2^781346813 is an apocalyptic number.

781346813 is a gapful number since it is divisible by the number (73) formed by its first and last digit.

It is an amenable number.

781346813 is a deficient number, since it is larger than the sum of its proper divisors (71631355).

781346813 is a wasteful number, since it uses less digits than its factorization.

781346813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 823423.

The product of its digits is 96768, while the sum is 41.

The square root of 781346813 is about 27952.5815086907. The cubic root of 781346813 is about 921.0459170505.

The spelling of 781346813 in words is "seven hundred eighty-one million, three hundred forty-six thousand, eight hundred thirteen".