161243917380 has 288 divisors, whose sum is σ = 620807443200. Its totient is φ = 34020559872.

The previous prime is 161243917363. The next prime is 161243917441. The reversal of 161243917380 is 83719342161.

161243917380 is a `hidden beast` number, since 16 + 1 + 243 + 9 + 17 + 380 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 512616 + ... + 765024.

It is an arithmetic number, because the mean of its divisors is an integer number (2155581400).

Almost surely, 2^161243917380 is an apocalyptic number.

161243917380 is a gapful number since it is divisible by the number (10) 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 161243917380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (310403721600).

161243917380 is an abundant number, since it is smaller than the sum of its proper divisors (459563525820).

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

161243917380 is a wasteful number, since it uses less digits than its factorization.

161243917380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252460 (or 252439 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 161243917380 in words is "one hundred sixty-one billion, two hundred forty-three million, nine hundred seventeen thousand, three hundred eighty".