771680909 has 4 divisors (see below), whose sum is σ = 773463516. Its totient is φ = 769898304.

The previous prime is 771680867. The next prime is 771680929. The reversal of 771680909 is 909086177.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 909086177 = 43 ⋅21141539.

It can be written as a sum of positive squares in 2 ways, for example, as 225150025 + 546530884 = 15005^2 + 23378^2 .

It is a cyclic number.

It is not a de Polignac number, because 771680909 - 2²⁰ = 770632333 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 (771680929) 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, 890654 + ... + 891519.

It is an arithmetic number, because the mean of its divisors is an integer number (193365879).

Almost surely, 2^771680909 is an apocalyptic number.

It is an amenable number.

771680909 is a deficient number, since it is larger than the sum of its proper divisors (1782607).

771680909 is a wasteful number, since it uses less digits than its factorization.

771680909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1782606.

The product of its (nonzero) digits is 190512, while the sum is 47.

The square root of 771680909 is about 27779.1452172309. The cubic root of 771680909 is about 917.2321145722.

The spelling of 771680909 in words is "seven hundred seventy-one million, six hundred eighty thousand, nine hundred nine".