765830851991 has 4 divisors (see below), whose sum is σ = 778385456184. Its totient is φ = 753276247800.

The previous prime is 765830851967. The next prime is 765830852099. The reversal of 765830851991 is 199158038567.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 765830851991 - 2²⁶ = 765763743127 is a prime.

It is a super-2 number, since 2×765830851991² (a number of 25 digits) 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 (765830857991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6277302005 + ... + 6277302126.

It is an arithmetic number, because the mean of its divisors is an integer number (194596364046).

Almost surely, 2^765830851991 is an apocalyptic number.

765830851991 is a deficient number, since it is larger than the sum of its proper divisors (12554604193).

765830851991 is a wasteful number, since it uses less digits than its factorization.

765830851991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12554604192.

The product of its (nonzero) digits is 16329600, while the sum is 62.

The spelling of 765830851991 in words is "seven hundred sixty-five billion, eight hundred thirty million, eight hundred fifty-one thousand, nine hundred ninety-one".