168401781 has 8 divisors (see below), whose sum is σ = 249484160. Its totient is φ = 112267836.

The previous prime is 168401773. The next prime is 168401867. The reversal of 168401781 is 187104861.

168401781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 168401781 - 2³ = 168401773 is a prime.

It is a super-2 number, since 2×168401781² = 56718319687943922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168401741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3118525 + ... + 3118578.

It is an arithmetic number, because the mean of its divisors is an integer number (31185520).

Almost surely, 2^168401781 is an apocalyptic number.

It is an amenable number.

168401781 is a deficient number, since it is larger than the sum of its proper divisors (81082379).

168401781 is an equidigital number, since it uses as much as digits as its factorization.

168401781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6237112 (or 6237106 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 168401781 is about 12976.9711797476. The cubic root of 168401781 is about 552.2243594115.

The spelling of 168401781 in words is "one hundred sixty-eight million, four hundred one thousand, seven hundred eighty-one".