405818117117821 has 8 divisors (see below), whose sum is σ = 437111313420320. Its totient is φ = 375518355618672.

The previous prime is 405818117117759. The next prime is 405818117117929. The reversal of 405818117117821 is 128711711818504.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 405818117117821 - 2⁴⁷ = 265080628762493 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 (405818117111821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 248358699990 + ... + 248358701623.

It is an arithmetic number, because the mean of its divisors is an integer number (54638914177540).

Almost surely, 2^{405818117117821} is an apocalyptic number.

It is an amenable number.

405818117117821 is a deficient number, since it is larger than the sum of its proper divisors (31293196302499).

405818117117821 is a wasteful number, since it uses less digits than its factorization.

405818117117821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496717401675.

The product of its (nonzero) digits is 1003520, while the sum is 55.

The spelling of 405818117117821 in words is "four hundred five trillion, eight hundred eighteen billion, one hundred seventeen million, one hundred seventeen thousand, eight hundred twenty-one".