1978943173237 has 2 divisors, whose sum is σ = 1978943173238. Its totient is φ = 1978943173236.

The previous prime is 1978943173117. The next prime is 1978943173241. The reversal of 1978943173237 is 7323713498791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1300715159121 + 678228014116 = 1140489^2 + 823546^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978943173237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1978943173037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989471586618 + 989471586619.

It is an arithmetic number, because the mean of its divisors is an integer number (989471586619).

Almost surely, 2^{1978943173237} is an apocalyptic number.

It is an amenable number.

1978943173237 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978943173237 is an equidigital number, since it uses as much as digits as its factorization.

1978943173237 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48009024, while the sum is 64.

The spelling of 1978943173237 in words is "one trillion, nine hundred seventy-eight billion, nine hundred forty-three million, one hundred seventy-three thousand, two hundred thirty-seven".