161605100 has 36 divisors (see below), whose sum is σ = 352560768. Its totient is φ = 64296000.

The previous prime is 161605097. The next prime is 161605121. The reversal of 161605100 is 1506161.

It is a happy number.

It is a super-3 number, since 3×161605100³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14870 + ... + 23330.

Almost surely, 2^161605100 is an apocalyptic number.

161605100 is a gapful number since it is divisible by the number (10) 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 161605100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (176280384).

161605100 is an abundant number, since it is smaller than the sum of its proper divisors (190955668).

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

161605100 is a wasteful number, since it uses less digits than its factorization.

161605100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8666 (or 8659 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 161605100 is about 12712.3994587961. The cubic root of 161605100 is about 544.6928662543.

The spelling of 161605100 in words is "one hundred sixty-one million, six hundred five thousand, one hundred".