161309825 has 12 divisors (see below), whose sum is σ = 205431420. Its totient is φ = 125559360.

The previous prime is 161309801. The next prime is 161309851. The reversal of 161309825 is 528903161.

It can be written as a sum of positive squares in 6 ways, for example, as 628849 + 160680976 = 793^2 + 12676^2 .

It is not a de Polignac number, because 161309825 - 2¹⁴ = 161293441 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 86270 + ... + 88119.

It is an arithmetic number, because the mean of its divisors is an integer number (17119285).

Almost surely, 2^161309825 is an apocalyptic number.

It is an amenable number.

161309825 is a deficient number, since it is larger than the sum of its proper divisors (44121595).

161309825 is a wasteful number, since it uses less digits than its factorization.

161309825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174436 (or 174431 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 161309825 is about 12700.7804878283. The cubic root of 161309825 is about 544.3609207874.

The spelling of 161309825 in words is "one hundred sixty-one million, three hundred nine thousand, eight hundred twenty-five".