161231616 has 216 divisors, whose sum is σ = 572892320. Its totient is φ = 42467328.

The previous prime is 161231611. The next prime is 161231659. The reversal of 161231616 is 616132161.

161231616 is a `hidden beast` number, since 1 + 6 + 12 + 31 + 616 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 161231616.

It is not an unprimeable number, because it can be changed into a prime (161231611) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 209280 + ... + 210048.

Almost surely, 2^161231616 is an apocalyptic number.

161231616 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 161231616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (286446160).

161231616 is an abundant number, since it is smaller than the sum of its proper divisors (411660704).

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

161231616 is a wasteful number, since it uses less digits than its factorization.

161231616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 811 (or 794 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 161231616 is about 12697.7012092741. The cubic root of 161231616 is about 544.2729310952.

Adding to 161231616 its reverse (616132161), we get a palindrome (777363777).

The spelling of 161231616 in words is "one hundred sixty-one million, two hundred thirty-one thousand, six hundred sixteen".