765861641661 has 4 divisors (see below), whose sum is σ = 1021148855552. Its totient is φ = 510574427772.

The previous prime is 765861641659. The next prime is 765861641663. The reversal of 765861641661 is 166146168567.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (765861641659) and next prime (765861641663).

It is not a de Polignac number, because 765861641661 - 2¹ = 765861641659 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (765861641663) 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, 127643606941 + ... + 127643606946.

It is an arithmetic number, because the mean of its divisors is an integer number (255287213888).

Almost surely, 2^765861641661 is an apocalyptic number.

It is an amenable number.

765861641661 is a deficient number, since it is larger than the sum of its proper divisors (255287213891).

765861641661 is a wasteful number, since it uses less digits than its factorization.

765861641661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255287213890.

The product of its digits is 8709120, while the sum is 57.

The spelling of 765861641661 in words is "seven hundred sixty-five billion, eight hundred sixty-one million, six hundred forty-one thousand, six hundred sixty-one".