161556725320 has 32 divisors (see below), whose sum is σ = 363912523200. Its totient is φ = 64549820608.

The previous prime is 161556725303. The next prime is 161556725329. The reversal of 161556725320 is 23527655161.

It is a super-2 number, since 2×161556725320² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161556725329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2241250 + ... + 2312209.

It is an arithmetic number, because the mean of its divisors is an integer number (11372266350).

Almost surely, 2^161556725320 is an apocalyptic number.

161556725320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161556725320 is an abundant number, since it is smaller than the sum of its proper divisors (202355797880).

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

161556725320 is a wasteful number, since it uses less digits than its factorization.

161556725320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4554357 (or 4554353 counting only the distinct ones).

The product of its (nonzero) digits is 378000, while the sum is 43.

The spelling of 161556725320 in words is "one hundred sixty-one billion, five hundred fifty-six million, seven hundred twenty-five thousand, three hundred twenty".