161644 has 24 divisors (see below), whose sum is σ = 338688. Its totient is φ = 66000.

The previous prime is 161641. The next prime is 161659. The reversal of 161644 is 446161.

161644 = T₇ + T₈ + ... + T₉₈.

It is a super-2 number, since 2×161644² = 52257565472, which contains 22 as substring.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (161641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 519 + ... + 769.

It is an arithmetic number, because the mean of its divisors is an integer number (14112).

2¹⁶¹⁶⁴⁴ is an apocalyptic number.

161644 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (169344).

161644 is an abundant number, since it is smaller than the sum of its proper divisors (177044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161644 is a wasteful number, since it uses less digits than its factorization.

161644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285 (or 283 counting only the distinct ones).

The product of its digits is 576, while the sum is 22.

The square root of 161644 is about 402.0497481656. The cubic root of 161644 is about 54.4736567129.

It can be divided in two parts, 161 and 644, that multiplied together give a square (103684 = 322²).

The spelling of 161644 in words is "one hundred sixty-one thousand, six hundred forty-four".