776772661 has 4 divisors (see below), whose sum is σ = 887740192. Its totient is φ = 665805132.

The previous prime is 776772637. The next prime is 776772691. The reversal of 776772661 is 166277677.

776772661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 166277677 = 29 ⋅5733713.

It is a cyclic number.

It is not a de Polignac number, because 776772661 - 2¹⁷ = 776641589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (776772691) 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, 55483755 + ... + 55483768.

It is an arithmetic number, because the mean of its divisors is an integer number (221935048).

Almost surely, 2^776772661 is an apocalyptic number.

It is an amenable number.

776772661 is a deficient number, since it is larger than the sum of its proper divisors (110967531).

776772661 is a wasteful number, since it uses less digits than its factorization.

776772661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110967530.

The product of its digits is 1037232, while the sum is 49.

The square root of 776772661 is about 27870.6415606100. The cubic root of 776772661 is about 919.2450726465.

The spelling of 776772661 in words is "seven hundred seventy-six million, seven hundred seventy-two thousand, six hundred sixty-one".