161677172281 has 3 divisors (see below), whose sum is σ = 161677574373. Its totient is φ = 161676770190.

The previous prime is 161677172273. The next prime is 161677172291. The reversal of 161677172281 is 182271776161.

The square root of 161677172281 is 402091.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 182271776161 = 27749 ⋅6568589.

It is not a de Polignac number, because 161677172281 - 2³ = 161677172273 is a prime.

It is a super-2 number, since 2×161677172281² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161677172201) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 201046 + ... + 603136.

It is an arithmetic number, because the mean of its divisors is an integer number (53892524791).

Almost surely, 2^161677172281 is an apocalyptic number.

161677172281 is the 402091-st square number.

161677172281 is the 201046-th centered octagonal number.

It is an amenable number.

161677172281 is a deficient number, since it is larger than the sum of its proper divisors (402092).

161677172281 is an frugal number, since it uses more digits than its factorization.

161677172281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804182 (or 402091 counting only the distinct ones).

The product of its digits is 395136, while the sum is 49.

Multiplying 161677172281 by its sum of digits (49), we get a square (7922181441769 = 2814637²).

The spelling of 161677172281 in words is "one hundred sixty-one billion, six hundred seventy-seven million, one hundred seventy-two thousand, two hundred eighty-one".