161329503 has 4 divisors (see below), whose sum is σ = 215106008. Its totient is φ = 107553000.

The previous prime is 161329481. The next prime is 161329529. The reversal of 161329503 is 305923161.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 161329503 - 2⁵ = 161329471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161329543) 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 3 ways as a sum of consecutive naturals, for example, 26888248 + ... + 26888253.

It is an arithmetic number, because the mean of its divisors is an integer number (53776502).

Almost surely, 2^161329503 is an apocalyptic number.

161329503 is a deficient number, since it is larger than the sum of its proper divisors (53776505).

161329503 is an equidigital number, since it uses as much as digits as its factorization.

161329503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53776504.

The product of its (nonzero) digits is 4860, while the sum is 30.

The square root of 161329503 is about 12701.5551410054. Note that the first 3 decimals coincide. The cubic root of 161329503 is about 544.3830552082.

The spelling of 161329503 in words is "one hundred sixty-one million, three hundred twenty-nine thousand, five hundred three".