1989666977 has 2 divisors, whose sum is σ = 1989666978. Its totient is φ = 1989666976.

The previous prime is 1989666937. The next prime is 1989667013. The reversal of 1989666977 is 7796669891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1224370081 + 765296896 = 34991^2 + 27664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1989666977 is a prime.

It is not a weakly prime, because it can be changed into another prime (1989666937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994833488 + 994833489.

It is an arithmetic number, because the mean of its divisors is an integer number (994833489).

Almost surely, 2^1989666977 is an apocalyptic number.

It is an amenable number.

1989666977 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989666977 is an equidigital number, since it uses as much as digits as its factorization.

1989666977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61725888, while the sum is 68.

The square root of 1989666977 is about 44605.6832365563. The cubic root of 1989666977 is about 1257.7475035042.

The spelling of 1989666977 in words is "one billion, nine hundred eighty-nine million, six hundred sixty-six thousand, nine hundred seventy-seven".