1978876117 has 2 divisors, whose sum is σ = 1978876118. Its totient is φ = 1978876116.

The previous prime is 1978876091. The next prime is 1978876129. The reversal of 1978876117 is 7116788791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1131716881 + 847159236 = 33641^2 + 29106^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978876117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1978876147) 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, 989438058 + 989438059.

It is an arithmetic number, because the mean of its divisors is an integer number (989438059).

Almost surely, 2^1978876117 is an apocalyptic number.

It is an amenable number.

1978876117 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978876117 is an equidigital number, since it uses as much as digits as its factorization.

1978876117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1185408, while the sum is 55.

The square root of 1978876117 is about 44484.5604339303. The cubic root of 1978876117 is about 1255.4696034689.

The spelling of 1978876117 in words is "one billion, nine hundred seventy-eight million, eight hundred seventy-six thousand, one hundred seventeen".