161779549 has 2 divisors, whose sum is σ = 161779550. Its totient is φ = 161779548.

The previous prime is 161779529. The next prime is 161779567. The reversal of 161779549 is 945977161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144432324 + 17347225 = 12018^2 + 4165^2 .

It is a cyclic number.

It is not a de Polignac number, because 161779549 - 2¹¹ = 161777501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161779529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80889774 + 80889775.

It is an arithmetic number, because the mean of its divisors is an integer number (80889775).

Almost surely, 2^161779549 is an apocalyptic number.

It is an amenable number.

161779549 is a deficient number, since it is larger than the sum of its proper divisors (1).

161779549 is an equidigital number, since it uses as much as digits as its factorization.

161779549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 476280, while the sum is 49.

The square root of 161779549 is about 12719.2589799878. The cubic root of 161779549 is about 544.8887902593. Note that the first 3 decimals are identical.

The spelling of 161779549 in words is "one hundred sixty-one million, seven hundred seventy-nine thousand, five hundred forty-nine".