168542261 has 4 divisors (see below), whose sum is σ = 168568524. Its totient is φ = 168516000.

The previous prime is 168542239. The next prime is 168542263. The reversal of 168542261 is 162245861.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 162245861 = 5651 ⋅28711.

It can be written as a sum of positive squares in 2 ways, for example, as 10562500 + 157979761 = 3250^2 + 12569^2 .

It is a cyclic number.

It is not a de Polignac number, because 168542261 - 2¹⁸ = 168280117 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 (168542263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3611 + ... + 18711.

It is an arithmetic number, because the mean of its divisors is an integer number (42142131).

Almost surely, 2^168542261 is an apocalyptic number.

It is an amenable number.

168542261 is a deficient number, since it is larger than the sum of its proper divisors (26263).

168542261 is a wasteful number, since it uses less digits than its factorization.

168542261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26262.

The product of its digits is 23040, while the sum is 35.

The square root of 168542261 is about 12982.3827165894. The cubic root of 168542261 is about 552.3778710831.

The spelling of 168542261 in words is "one hundred sixty-eight million, five hundred forty-two thousand, two hundred sixty-one".