161534821 has 8 divisors (see below), whose sum is σ = 188379200. Its totient is φ = 138458124.

The previous prime is 161534803. The next prime is 161534837. The reversal of 161534821 is 128435161.

It is not a de Polignac number, because 161534821 - 2⁹ = 161534309 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 (161534801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 235131 + ... + 235816.

It is an arithmetic number, because the mean of its divisors is an integer number (23547400).

Almost surely, 2^161534821 is an apocalyptic number.

It is an amenable number.

161534821 is a deficient number, since it is larger than the sum of its proper divisors (26844379).

161534821 is an frugal number, since it uses more digits than its factorization.

161534821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470968 (or 470954 counting only the distinct ones).

The product of its digits is 5760, while the sum is 31.

The square root of 161534821 is about 12709.6349672207. The cubic root of 161534821 is about 544.6138959321.

Adding to 161534821 its reverse (128435161), we get a palindrome (289969982).

The spelling of 161534821 in words is "one hundred sixty-one million, five hundred thirty-four thousand, eight hundred twenty-one".