168139081 has 4 divisors (see below), whose sum is σ = 183424464. Its totient is φ = 152853700.

The previous prime is 168139079. The next prime is 168139087. The reversal of 168139081 is 180931861.

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 a cyclic number.

It is not a de Polignac number, because 168139081 - 2¹ = 168139079 is a prime.

It is a super-2 number, since 2×168139081² = 56541501119049122, which contains 22 as substring.

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 168139081.

It is not an unprimeable number, because it can be changed into a prime (168139087) 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, 7642675 + ... + 7642696.

It is an arithmetic number, because the mean of its divisors is an integer number (45856116).

Almost surely, 2^168139081 is an apocalyptic number.

168139081 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

168139081 is a deficient number, since it is larger than the sum of its proper divisors (15285383).

168139081 is a wasteful number, since it uses less digits than its factorization.

168139081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15285382.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 168139081 is about 12966.8454529234. The cubic root of 168139081 is about 551.9370607106.

The spelling of 168139081 in words is "one hundred sixty-eight million, one hundred thirty-nine thousand, eighty-one".