161118521 has 4 divisors (see below), whose sum is σ = 163059792. Its totient is φ = 159177252.

The previous prime is 161118511. The next prime is 161118527. The reversal of 161118521 is 125811161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 161118521 - 2⁶ = 161118457 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161118527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 970511 + ... + 970676.

It is an arithmetic number, because the mean of its divisors is an integer number (40764948).

Almost surely, 2^161118521 is an apocalyptic number.

It is an amenable number.

161118521 is a deficient number, since it is larger than the sum of its proper divisors (1941271).

161118521 is an equidigital number, since it uses as much as digits as its factorization.

161118521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1941270.

The product of its digits is 480, while the sum is 26.

The square root of 161118521 is about 12693.2470629071. The cubic root of 161118521 is about 544.1456422779.

Adding to 161118521 its reverse (125811161), we get a palindrome (286929682).

The spelling of 161118521 in words is "one hundred sixty-one million, one hundred eighteen thousand, five hundred twenty-one".