168539839621 has 4 divisors (see below), whose sum is σ = 178453947852. Its totient is φ = 158625731392.

The previous prime is 168539839619. The next prime is 168539839673. The reversal of 168539839621 is 126938935861.

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

It can be written as a sum of positive squares in 2 ways, for example, as 155382602596 + 13157237025 = 394186^2 + 114705^2 .

It is not a de Polignac number, because 168539839621 - 2¹ = 168539839619 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 168539839621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168539839421) 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, 4957054090 + ... + 4957054123.

It is an arithmetic number, because the mean of its divisors is an integer number (44613486963).

Almost surely, 2^168539839621 is an apocalyptic number.

It is an amenable number.

168539839621 is a deficient number, since it is larger than the sum of its proper divisors (9914108231).

168539839621 is an equidigital number, since it uses as much as digits as its factorization.

168539839621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9914108230.

The product of its digits is 16796160, while the sum is 61.

The spelling of 168539839621 in words is "one hundred sixty-eight billion, five hundred thirty-nine million, eight hundred thirty-nine thousand, six hundred twenty-one".