161391825 has 48 divisors (see below), whose sum is σ = 338847360. Its totient is φ = 73776960.

The previous prime is 161391793. The next prime is 161391827. The reversal of 161391825 is 528193161.

161391825 is a `hidden beast` number, since 1 + 613 + 9 + 18 + 25 = 666.

161391825 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 161391825 - 2⁵ = 161391793 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161391825.

It is not an unprimeable number, because it can be changed into a prime (161391827) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12354 + ... + 21803.

It is an arithmetic number, because the mean of its divisors is an integer number (7059320).

Almost surely, 2^161391825 is an apocalyptic number.

161391825 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161391825 is an abundant number, since it is smaller than the sum of its proper divisors (177455535).

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

161391825 is a wasteful number, since it uses less digits than its factorization.

161391825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34183 (or 34172 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 161391825 is about 12704.0082257530. The cubic root of 161391825 is about 544.4531450397.

The spelling of 161391825 in words is "one hundred sixty-one million, three hundred ninety-one thousand, eight hundred twenty-five".