7875785781 has 12 divisors (see below), whose sum is σ = 11383182720. Its totient is φ = 5247271080.

The previous prime is 7875785761. The next prime is 7875785791. The reversal of 7875785781 is 1875875787.

7875785781 is a `hidden beast` number, since 7 + 8 + 7 + 57 + 8 + 578 + 1 = 666.

It is not a de Polignac number, because 7875785781 - 2¹¹ = 7875783733 is a prime.

It is a super-2 number, since 2×7875785781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7875785761) 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, 255685 + ... + 284826.

It is an arithmetic number, because the mean of its divisors is an integer number (948598560).

Almost surely, 2^7875785781 is an apocalyptic number.

It is an amenable number.

7875785781 is a deficient number, since it is larger than the sum of its proper divisors (3507396939).

7875785781 is a wasteful number, since it uses less digits than its factorization.

7875785781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542136 (or 542133 counting only the distinct ones).

The product of its digits is 30732800, while the sum is 63.

The square root of 7875785781 is about 88745.6240104266. The cubic root of 7875785781 is about 1989.5947746056.

The spelling of 7875785781 in words is "seven billion, eight hundred seventy-five million, seven hundred eighty-five thousand, seven hundred eighty-one".