161605540 has 12 divisors (see below), whose sum is σ = 339371676. Its totient is φ = 64642208.

The previous prime is 161605523. The next prime is 161605571. The reversal of 161605540 is 45506161.

161605540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 39237696 + 122367844 = 6264^2 + 11062^2 .

It is a super-2 number, since 2×161605540² = 52232701117383200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161605499 and 161605508.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4040119 + ... + 4040158.

It is an arithmetic number, because the mean of its divisors is an integer number (28280973).

Almost surely, 2^161605540 is an apocalyptic number.

161605540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161605540 is an abundant number, since it is smaller than the sum of its proper divisors (177766136).

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

161605540 is a wasteful number, since it uses less digits than its factorization.

161605540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8080286 (or 8080284 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 161605540 is about 12712.4167647226. The cubic root of 161605540 is about 544.6933605965.

The spelling of 161605540 in words is "one hundred sixty-one million, six hundred five thousand, five hundred forty".