781664347089 has 12 divisors (see below), whose sum is σ = 1129094967156. Its totient is φ = 521098375392.

The previous prime is 781664347081. The next prime is 781664347099. The reversal of 781664347089 is 980743466187.

781664347089 is a `hidden beast` number, since 7 + 81 + 6 + 6 + 4 + 3 + 470 + 89 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 602890131600 + 178774215489 = 776460^2 + 422817^2 .

It is not a de Polignac number, because 781664347089 - 2³ = 781664347081 is a prime.

It is a super-2 number, since 2×781664347089² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (781664347081) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 478374 + ... + 1338719.

It is an arithmetic number, because the mean of its divisors is an integer number (94091247263).

Almost surely, 2^781664347089 is an apocalyptic number.

It is an amenable number.

781664347089 is a deficient number, since it is larger than the sum of its proper divisors (347430620067).

781664347089 is a wasteful number, since it uses less digits than its factorization.

781664347089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1864896 (or 1864893 counting only the distinct ones).

The product of its (nonzero) digits is 48771072, while the sum is 63.

It can be divided in two parts, 781664 and 347089, that added together give a triangular number (1128753 = T₁₅₀₂).

The spelling of 781664347089 in words is "seven hundred eighty-one billion, six hundred sixty-four million, three hundred forty-seven thousand, eighty-nine".