161655680 has 64 divisors (see below), whose sum is σ = 388497600. Its totient is φ = 64321536.

The previous prime is 161655677. The next prime is 161655709. The reversal of 161655680 is 86556161.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×161655680² = 52265117752524800, which contains 22 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 (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 146009 + ... + 147111.

It is an arithmetic number, because the mean of its divisors is an integer number (6070275).

Almost surely, 2^161655680 is an apocalyptic number.

161655680 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 161655680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (194248800).

161655680 is an abundant number, since it is smaller than the sum of its proper divisors (226841920).

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

161655680 is a wasteful number, since it uses less digits than its factorization.

161655680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1351 (or 1339 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 161655680 is about 12714.3886994224. The cubic root of 161655680 is about 544.7496872568.

The spelling of 161655680 in words is "one hundred sixty-one million, six hundred fifty-five thousand, six hundred eighty".