161156720 has 20 divisors (see below), whose sum is σ = 374689560. Its totient is φ = 64462656.

The previous prime is 161156717. The next prime is 161156783. The reversal of 161156720 is 27651161.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-3 number, since 3×161156720³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1007150 + ... + 1007309.

It is an arithmetic number, because the mean of its divisors is an integer number (18734478).

Almost surely, 2^161156720 is an apocalyptic number.

161156720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161156720 is an abundant number, since it is smaller than the sum of its proper divisors (213532840).

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

161156720 is a wasteful number, since it uses less digits than its factorization.

161156720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2014472 (or 2014466 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 161156720 is about 12694.7516714586. The cubic root of 161156720 is about 544.1886420456.

The spelling of 161156720 in words is "one hundred sixty-one million, one hundred fifty-six thousand, seven hundred twenty".