161644544 has 32 divisors (see below), whose sum is σ = 323349690. Its totient is φ = 80805888.

The previous prime is 161644523. The next prime is 161644547. The reversal of 161644544 is 445446161.

It can be written as a sum of positive squares in only one way, i.e., 147865600 + 13778944 = 12160^2 + 3712^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×161644544² = 52257917209935872, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161644547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30302 + ... + 35234.

Almost surely, 2^161644544 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161644544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161674845).

161644544 is an abundant number, since it is smaller than the sum of its proper divisors (161705146).

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

161644544 is an frugal number, since it uses more digits than its factorization.

161644544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4963 (or 4935 counting only the distinct ones).

The product of its digits is 46080, while the sum is 35.

The square root of 161644544 is about 12713.9507628432. The cubic root of 161644544 is about 544.7371782174.

The spelling of 161644544 in words is "one hundred sixty-one million, six hundred forty-four thousand, five hundred forty-four".