161978293 has 2 divisors, whose sum is σ = 161978294. Its totient is φ = 161978292.

The previous prime is 161978273. The next prime is 161978339. The reversal of 161978293 is 392879161.

It is a happy number.

It is an a-pointer prime, because the next prime (161978339) can be obtained adding 161978293 to its sum of digits (46).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161976529 + 1764 = 12727^2 + 42^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161978293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161978233) 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, 80989146 + 80989147.

It is an arithmetic number, because the mean of its divisors is an integer number (80989147).

Almost surely, 2^161978293 is an apocalyptic number.

It is an amenable number.

161978293 is a deficient number, since it is larger than the sum of its proper divisors (1).

161978293 is an equidigital number, since it uses as much as digits as its factorization.

161978293 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 46.

The square root of 161978293 is about 12727.0693012964. The cubic root of 161978293 is about 545.1118284678. Note that the first 3 decimals are identical.

The spelling of 161978293 in words is "one hundred sixty-one million, nine hundred seventy-eight thousand, two hundred ninety-three".