161636436 has 72 divisors (see below), whose sum is σ = 443397864. Its totient is φ = 49351680.

The previous prime is 161636413. The next prime is 161636467. The reversal of 161636436 is 634636161.

161636436 is a `hidden beast` number, since 1 + 6 + 1 + 6 + 3 + 643 + 6 = 666.

161636436 is digitally balanced in base 3 and base 9, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 3027600 + 158608836 = 1740^2 + 12594^2 .

It is a super-2 number, since 2×161636436² = 52252674885564192, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

161636436 is strictly pandigital in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 161636436.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62856 + ... + 65376.

Almost surely, 2^161636436 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 161636436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221698932).

161636436 is an abundant number, since it is smaller than the sum of its proper divisors (281761428).

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

161636436 is a wasteful number, since it uses less digits than its factorization.

161636436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2681 (or 2676 counting only the distinct ones).

The product of its digits is 46656, while the sum is 36.

The square root of 161636436 is about 12713.6318965117. The cubic root of 161636436 is about 544.7280701609.

The spelling of 161636436 in words is "one hundred sixty-one million, six hundred thirty-six thousand, four hundred thirty-six".