161951773 has 2 divisors, whose sum is σ = 161951774. Its totient is φ = 161951772.

The previous prime is 161951771. The next prime is 161951789. The reversal of 161951773 is 377159161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83576164 + 78375609 = 9142^2 + 8853^2 .

It is a cyclic number.

It is not a de Polignac number, because 161951773 - 2¹ = 161951771 is a prime.

Together with 161951771, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161951771) 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, 80975886 + 80975887.

It is an arithmetic number, because the mean of its divisors is an integer number (80975887).

Almost surely, 2^161951773 is an apocalyptic number.

It is an amenable number.

161951773 is a deficient number, since it is larger than the sum of its proper divisors (1).

161951773 is an equidigital number, since it uses as much as digits as its factorization.

161951773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39690, while the sum is 40.

The square root of 161951773 is about 12726.0273848519. The cubic root of 161951773 is about 545.0820772494.

The spelling of 161951773 in words is "one hundred sixty-one million, nine hundred fifty-one thousand, seven hundred seventy-three".