161758720 has 80 divisors (see below), whose sum is σ = 391113360. Its totient is φ = 64159744.

The previous prime is 161758717. The next prime is 161758739. The reversal of 161758720 is 27857161.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 161758720.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 458064 + ... + 458416.

It is an arithmetic number, because the mean of its divisors is an integer number (4888917).

Almost surely, 2^161758720 is an apocalyptic number.

161758720 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 161758720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (195556680).

161758720 is an abundant number, since it is smaller than the sum of its proper divisors (229354640).

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

161758720 is an equidigital number, since it uses as much as digits as its factorization.

161758720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 37.

The square root of 161758720 is about 12718.4401559311. The cubic root of 161758720 is about 544.8654045764.

The spelling of 161758720 in words is "one hundred sixty-one million, seven hundred fifty-eight thousand, seven hundred twenty".