168140491 has 4 divisors (see below), whose sum is σ = 170029800. Its totient is φ = 166251184.

The previous prime is 168140471. The next prime is 168140509. The reversal of 168140491 is 194041861.

168140491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 194041861 = 13 ⋅14926297.

It is a cyclic number.

It is not a de Polignac number, because 168140491 - 2²³ = 159751883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (168140411) 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, 944521 + ... + 944698.

It is an arithmetic number, because the mean of its divisors is an integer number (42507450).

Almost surely, 2^168140491 is an apocalyptic number.

168140491 is a deficient number, since it is larger than the sum of its proper divisors (1889309).

168140491 is an equidigital number, since it uses as much as digits as its factorization.

168140491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1889308.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 168140491 is about 12966.8998222397. The cubic root of 168140491 is about 551.9386035386.

The spelling of 168140491 in words is "one hundred sixty-eight million, one hundred forty thousand, four hundred ninety-one".