161723520 has 384 divisors, whose sum is σ = 669772800. Its totient is φ = 36771840.

The previous prime is 161723509. The next prime is 161723521. The reversal of 161723520 is 25327161.

It is a happy number.

161723520 is a `hidden beast` number, since 1 + 617 + 23 + 5 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (161723521) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 846625 + ... + 846815.

It is an arithmetic number, because the mean of its divisors is an integer number (1744200).

Almost surely, 2^161723520 is an apocalyptic number.

161723520 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 161723520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (334886400).

161723520 is an abundant number, since it is smaller than the sum of its proper divisors (508049280).

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

161723520 is a wasteful number, since it uses less digits than its factorization.

161723520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233 (or 208 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 161723520 is about 12717.0562631452. The cubic root of 161723520 is about 544.8258793428.

The spelling of 161723520 in words is "one hundred sixty-one million, seven hundred twenty-three thousand, five hundred twenty".