1678138961 has 2 divisors, whose sum is σ = 1678138962. Its totient is φ = 1678138960.

The previous prime is 1678138927. The next prime is 1678138991. The reversal of 1678138961 is 1698318761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1110222400 + 567916561 = 33320^2 + 23831^2 .

It is an emirp because it is prime and its reverse (1698318761) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1678138961 - 2¹⁴ = 1678122577 is a prime.

It is not a weakly prime, because it can be changed into another prime (1678138921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 839069480 + 839069481.

It is an arithmetic number, because the mean of its divisors is an integer number (839069481).

Almost surely, 2^1678138961 is an apocalyptic number.

It is an amenable number.

1678138961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1678138961 is an equidigital number, since it uses as much as digits as its factorization.

1678138961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 50.

The square root of 1678138961 is about 40965.0944219588. The cubic root of 1678138961 is about 1188.3452652463.

The spelling of 1678138961 in words is "one billion, six hundred seventy-eight million, one hundred thirty-eight thousand, nine hundred sixty-one".