161555723140 has 96 divisors (see below), whose sum is σ = 400404953088. Its totient is φ = 53581824000.

The previous prime is 161555723137. The next prime is 161555723177. The reversal of 161555723140 is 41327555161.

It is a happy number.

161555723140 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×161555723140² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161555723093 and 161555723102.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13278660 + ... + 13290820.

It is an arithmetic number, because the mean of its divisors is an integer number (4170884928).

Almost surely, 2^161555723140 is an apocalyptic number.

161555723140 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 161555723140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (200202476544).

161555723140 is an abundant number, since it is smaller than the sum of its proper divisors (238849229948).

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

161555723140 is a wasteful number, since it uses less digits than its factorization.

161555723140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15269 (or 15267 counting only the distinct ones).

The product of its (nonzero) digits is 126000, while the sum is 40.

The spelling of 161555723140 in words is "one hundred sixty-one billion, five hundred fifty-five million, seven hundred twenty-three thousand, one hundred forty".