168535821 has 4 divisors (see below), whose sum is σ = 224714432. Its totient is φ = 112357212.

The previous prime is 168535819. The next prime is 168535853. The reversal of 168535821 is 128535861.

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 not a de Polignac number, because 168535821 - 2¹ = 168535819 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 168535821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168535811) 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 3 ways as a sum of consecutive naturals, for example, 28089301 + ... + 28089306.

It is an arithmetic number, because the mean of its divisors is an integer number (56178608).

Almost surely, 2^168535821 is an apocalyptic number.

It is an amenable number.

168535821 is a deficient number, since it is larger than the sum of its proper divisors (56178611).

168535821 is an equidigital number, since it uses as much as digits as its factorization.

168535821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56178610.

The product of its digits is 57600, while the sum is 39.

The square root of 168535821 is about 12982.1346857903. The cubic root of 168535821 is about 552.3708355404.

The spelling of 168535821 in words is "one hundred sixty-eight million, five hundred thirty-five thousand, eight hundred twenty-one".