781711868261 has 8 divisors (see below), whose sum is σ = 792611364120. Its totient is φ = 770817537792.

The previous prime is 781711868243. The next prime is 781711868303. The reversal of 781711868261 is 162868117187.

It can be written as a sum of positive squares in 4 ways, for example, as 55645979236 + 726065889025 = 235894^2 + 852095^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-781711868261 is a prime.

It is a super-2 number, since 2×781711868261² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 781711868197 and 781711868206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781711864261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 986066 + ... + 1592403.

It is an arithmetic number, because the mean of its divisors is an integer number (99076420515).

Almost surely, 2^781711868261 is an apocalyptic number.

It is an amenable number.

781711868261 is a deficient number, since it is larger than the sum of its proper divisors (10899495859).

781711868261 is a wasteful number, since it uses less digits than its factorization.

781711868261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2582695.

The product of its digits is 1806336, while the sum is 56.

The spelling of 781711868261 in words is "seven hundred eighty-one billion, seven hundred eleven million, eight hundred sixty-eight thousand, two hundred sixty-one".