161005403 has 4 divisors (see below), whose sum is σ = 173390448. Its totient is φ = 148620360.

The previous prime is 161005399. The next prime is 161005417. The reversal of 161005403 is 304500161.

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

It is a cyclic number.

It is not a de Polignac number, because 161005403 - 2² = 161005399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161005433) 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, 6192503 + ... + 6192528.

It is an arithmetic number, because the mean of its divisors is an integer number (43347612).

Almost surely, 2^161005403 is an apocalyptic number.

161005403 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

161005403 is a deficient number, since it is larger than the sum of its proper divisors (12385045).

161005403 is a wasteful number, since it uses less digits than its factorization.

161005403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12385044.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 161005403 is about 12688.7904466896. The cubic root of 161005403 is about 544.0182679761.

Adding to 161005403 its reverse (304500161), we get a palindrome (465505564).

The spelling of 161005403 in words is "one hundred sixty-one million, five thousand, four hundred three".