161857133 has 8 divisors (see below), whose sum is σ = 164387448. Its totient is φ = 159335424.

The previous prime is 161857127. The next prime is 161857147. The reversal of 161857133 is 331758161.

It can be written as a sum of positive squares in 4 ways, for example, as 13675204 + 148181929 = 3698^2 + 12173^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161857133 - 2¹² = 161853037 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 161857093 and 161857102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161857103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42941 + ... + 46557.

It is an arithmetic number, because the mean of its divisors is an integer number (20548431).

Almost surely, 2^161857133 is an apocalyptic number.

It is an amenable number.

161857133 is a deficient number, since it is larger than the sum of its proper divisors (2530315).

161857133 is an equidigital number, since it uses as much as digits as its factorization.

161857133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4303.

The product of its digits is 15120, while the sum is 35.

The square root of 161857133 is about 12722.3084776309. The cubic root of 161857133 is about 544.9758797506.

The spelling of 161857133 in words is "one hundred sixty-one million, eight hundred fifty-seven thousand, one hundred thirty-three".