161581283136 has 1344 divisors, whose sum is σ = 636215623680. Its totient is φ = 39504568320.

The previous prime is 161581283131. The next prime is 161581283179. The reversal of 161581283136 is 631382185161.

161581283136 is a `hidden beast` number, since 1 + 6 + 1 + 581 + 2 + 8 + 31 + 36 = 666.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a super-2 number, since 2×161581283136² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161581283091 and 161581283100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161581283131) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1272293505 + ... + 1272293631.

It is an arithmetic number, because the mean of its divisors is an integer number (473374720).

Almost surely, 2^161581283136 is an apocalyptic number.

161581283136 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 161581283136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (318107811840).

161581283136 is an abundant number, since it is smaller than the sum of its proper divisors (474634340544).

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

161581283136 is a wasteful number, since it uses less digits than its factorization.

161581283136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 212 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The spelling of 161581283136 in words is "one hundred sixty-one billion, five hundred eighty-one million, two hundred eighty-three thousand, one hundred thirty-six".