168521139 has 6 divisors (see below), whose sum is σ = 243419436. Its totient is φ = 112347420.

The previous prime is 168521137. The next prime is 168521173. The reversal of 168521139 is 931125861.

It is not a de Polignac number, because 168521139 - 2¹ = 168521137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (168521137) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9362277 + ... + 9362294.

It is an arithmetic number, because the mean of its divisors is an integer number (40569906).

Almost surely, 2^168521139 is an apocalyptic number.

168521139 is a deficient number, since it is larger than the sum of its proper divisors (74898297).

168521139 is a wasteful number, since it uses less digits than its factorization.

168521139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18724577 (or 18724574 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 168521139 is about 12981.5692040677. The cubic root of 168521139 is about 552.3547951441.

The spelling of 168521139 in words is "one hundred sixty-eight million, five hundred twenty-one thousand, one hundred thirty-nine".