161601616 has 40 divisors (see below), whose sum is σ = 344986848. Its totient is φ = 72720000.

The previous prime is 161601613. The next prime is 161601617. The reversal of 161601616 is 616106161.

It is a super-2 number, since 2×161601616² = 52230164587622912, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161601613) 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, 13231 + ... + 22321.

Almost surely, 2^161601616 is an apocalyptic number.

161601616 is a gapful number since it is divisible by the number (16) 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 161601616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (172493424).

161601616 is an abundant number, since it is smaller than the sum of its proper divisors (183385232).

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

161601616 is a wasteful number, since it uses less digits than its factorization.

161601616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9211 (or 9205 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 161601616 is about 12712.2624264920. The cubic root of 161601616 is about 544.6889519315.

Adding to 161601616 its reverse (616106161), we get a palindrome (777707777).

The spelling of 161601616 in words is "one hundred sixty-one million, six hundred one thousand, six hundred sixteen".