1978936361 has 2 divisors, whose sum is σ = 1978936362. Its totient is φ = 1978936360.

The previous prime is 1978936339. The next prime is 1978936373. The reversal of 1978936361 is 1636398791.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1975269136 + 3667225 = 44444^2 + 1915^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978936361 is a prime.

It is not a weakly prime, because it can be changed into another prime (1978936331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989468180 + 989468181.

It is an arithmetic number, because the mean of its divisors is an integer number (989468181).

Almost surely, 2^1978936361 is an apocalyptic number.

It is an amenable number.

1978936361 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978936361 is an equidigital number, since it uses as much as digits as its factorization.

1978936361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1469664, while the sum is 53.

The square root of 1978936361 is about 44485.2375625892. The cubic root of 1978936361 is about 1255.4823436538.

The spelling of 1978936361 in words is "one billion, nine hundred seventy-eight million, nine hundred thirty-six thousand, three hundred sixty-one".