2161768777 has 4 divisors (see below), whose sum is σ = 2470592896. Its totient is φ = 1852944660.

The previous prime is 2161768733. The next prime is 2161768853. The reversal of 2161768777 is 7778671612.

It is a happy number.

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 not a de Polignac number, because 2161768777 - 2⁷ = 2161768649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2161768177) 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, 154412049 + ... + 154412062.

It is an arithmetic number, because the mean of its divisors is an integer number (617648224).

Almost surely, 2^2161768777 is an apocalyptic number.

It is an amenable number.

2161768777 is a deficient number, since it is larger than the sum of its proper divisors (308824119).

2161768777 is an equidigital number, since it uses as much as digits as its factorization.

2161768777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308824118.

The product of its digits is 1382976, while the sum is 52.

The square root of 2161768777 is about 46494.8252712063. The cubic root of 2161768777 is about 1293.0135616886.

The spelling of 2161768777 in words is "two billion, one hundred sixty-one million, seven hundred sixty-eight thousand, seven hundred seventy-seven".