168400136821 has 16 divisors (see below), whose sum is σ = 193988703744. Its totient is φ = 143198920944.

The previous prime is 168400136803. The next prime is 168400136831. The reversal of 168400136821 is 128631004861.

It is a cyclic number.

It is not a de Polignac number, because 168400136821 - 2¹⁹ = 168399612533 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 (168400136831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 262446 + ... + 636928.

It is an arithmetic number, because the mean of its divisors is an integer number (12124293984).

Almost surely, 2^168400136821 is an apocalyptic number.

It is an amenable number.

168400136821 is a deficient number, since it is larger than the sum of its proper divisors (25588566923).

168400136821 is a wasteful number, since it uses less digits than its factorization.

168400136821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375000.

The product of its (nonzero) digits is 55296, while the sum is 40.

The spelling of 168400136821 in words is "one hundred sixty-eight billion, four hundred million, one hundred thirty-six thousand, eight hundred twenty-one".