161725518 has 64 divisors (see below), whose sum is σ = 378100800. Its totient is φ = 51166080.

The previous prime is 161725517. The next prime is 161725519. The reversal of 161725518 is 815527161.

161725518 is a `hidden beast` number, since 1 + 617 + 25 + 5 + 18 = 666.

It is an interprime number because it is at equal distance from previous prime (161725517) and next prime (161725519).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161725517) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 94680 + ... + 96372.

It is an arithmetic number, because the mean of its divisors is an integer number (5907825).

Almost surely, 2^161725518 is an apocalyptic number.

161725518 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161725518, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189050400).

161725518 is an abundant number, since it is smaller than the sum of its proper divisors (216375282).

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

161725518 is a wasteful number, since it uses less digits than its factorization.

161725518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1794 (or 1788 counting only the distinct ones).

The product of its digits is 16800, while the sum is 36.

The square root of 161725518 is about 12717.1348188183. The cubic root of 161725518 is about 544.8281230024.

The spelling of 161725518 in words is "one hundred sixty-one million, seven hundred twenty-five thousand, five hundred eighteen".