161808636 has 96 divisors (see below), whose sum is σ = 437472000. Its totient is φ = 46033920.

The previous prime is 161808631. The next prime is 161808637. The reversal of 161808636 is 636808161.

It is a junction number, because it is equal to n+sod(n) for n = 161808594 and 161808603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161808631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 373476 + ... + 373908.

It is an arithmetic number, because the mean of its divisors is an integer number (4557000).

Almost surely, 2^161808636 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161808636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (218736000).

161808636 is an abundant number, since it is smaller than the sum of its proper divisors (275663364).

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

161808636 is a wasteful number, since it uses less digits than its factorization.

161808636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619 (or 617 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 161808636 is about 12720.4023521271. The cubic root of 161808636 is about 544.9214442229.

The spelling of 161808636 in words is "one hundred sixty-one million, eight hundred eight thousand, six hundred thirty-six".