2779231661 has 2 divisors, whose sum is σ = 2779231662. Its totient is φ = 2779231660.

The previous prime is 2779231643. The next prime is 2779231709. The reversal of 2779231661 is 1661329772.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2253400900 + 525830761 = 47470^2 + 22931^2 .

It is a cyclic number.

It is not a de Polignac number, because 2779231661 - 2¹⁴ = 2779215277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2779231601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1389615830 + 1389615831.

It is an arithmetic number, because the mean of its divisors is an integer number (1389615831).

Almost surely, 2^2779231661 is an apocalyptic number.

It is an amenable number.

2779231661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2779231661 is an equidigital number, since it uses as much as digits as its factorization.

2779231661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 44.

The square root of 2779231661 is about 52718.4186124736. The cubic root of 2779231661 is about 1405.9663165810.

The spelling of 2779231661 in words is "two billion, seven hundred seventy-nine million, two hundred thirty-one thousand, six hundred sixty-one".