765491861 has 8 divisors (see below), whose sum is σ = 812700504. Its totient is φ = 718525440.

The previous prime is 765491843. The next prime is 765491863. The reversal of 765491861 is 168194567.

765491861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 32706961 + 732784900 = 5719^2 + 27070^2 .

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 765491861 - 2¹⁰ = 765490837 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (765491863) 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, 54020 + ... + 66701.

It is an arithmetic number, because the mean of its divisors is an integer number (101587563).

Almost surely, 2^765491861 is an apocalyptic number.

It is an amenable number.

765491861 is a deficient number, since it is larger than the sum of its proper divisors (47208643).

765491861 is a wasteful number, since it uses less digits than its factorization.

765491861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121111.

The product of its digits is 362880, while the sum is 47.

The square root of 765491861 is about 27667.5235790990. The cubic root of 765491861 is about 914.7733962626.

The spelling of 765491861 in words is "seven hundred sixty-five million, four hundred ninety-one thousand, eight hundred sixty-one".