2778308661 has 8 divisors (see below), whose sum is σ = 3710833984. Its totient is φ = 1848994560.

The previous prime is 2778308633. The next prime is 2778308671. The reversal of 2778308661 is 1668038772.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2778308661 - 2⁹ = 2778308149 is a prime.

It is a super-2 number, since 2×2778308661² = 15437998031575225842, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2778308661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2778308671) 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, 800785 + ... + 804246.

It is an arithmetic number, because the mean of its divisors is an integer number (463854248).

Almost surely, 2^2778308661 is an apocalyptic number.

It is an amenable number.

2778308661 is a deficient number, since it is larger than the sum of its proper divisors (932525323).

2778308661 is a wasteful number, since it uses less digits than its factorization.

2778308661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1605611.

The product of its (nonzero) digits is 677376, while the sum is 48.

The square root of 2778308661 is about 52709.6638293207. The cubic root of 2778308661 is about 1405.8106559820.

The spelling of 2778308661 in words is "two billion, seven hundred seventy-eight million, three hundred eight thousand, six hundred sixty-one".