161858968489 has 9 divisors (see below), whose sum is σ = 167644856613. Its totient is φ = 156266359872.

The previous prime is 161858968477. The next prime is 161858968499. The reversal of 161858968489 is 984869858161.

The square root of 161858968489 is 402317.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 20115225 + 161838853264 = 4485^2 + 402292^2 .

It is not a de Polignac number, because 161858968489 - 2¹³ = 161858960297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161858968409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 11660257 + ... + 11674129.

Almost surely, 2^161858968489 is an apocalyptic number.

161858968489 is the 402317-th square number.

161858968489 is the 201159-th centered octagonal number.

It is an amenable number.

161858968489 is a deficient number, since it is larger than the sum of its proper divisors (5785888124).

161858968489 is an frugal number, since it uses more digits than its factorization.

161858968489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27804 (or 13902 counting only the distinct ones).

The product of its digits is 238878720, while the sum is 73.

The spelling of 161858968489 in words is "one hundred sixty-one billion, eight hundred fifty-eight million, nine hundred sixty-eight thousand, four hundred eighty-nine".