161645444 has 6 divisors (see below), whose sum is σ = 282879534. Its totient is φ = 80822720.

The previous prime is 161645443. The next prime is 161645447. The reversal of 161645444 is 444546161.

It can be written as a sum of positive squares in only one way, i.e., 157803844 + 3841600 = 12562^2 + 1960^2 .

It is a super-2 number, since 2×161645444² = 52258499131914272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161645441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20205677 + ... + 20205684.

It is an arithmetic number, because the mean of its divisors is an integer number (47146589).

Almost surely, 2^161645444 is an apocalyptic number.

It is an amenable number.

161645444 is a deficient number, since it is larger than the sum of its proper divisors (121234090).

161645444 is a wasteful number, since it uses less digits than its factorization.

161645444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40411365 (or 40411363 counting only the distinct ones).

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

The square root of 161645444 is about 12713.9861569848. The cubic root of 161645444 is about 544.7381892063.

The spelling of 161645444 in words is "one hundred sixty-one million, six hundred forty-five thousand, four hundred forty-four".