405685891 has 16 divisors (see below), whose sum is σ = 479888640. Its totient is φ = 339340320.

The previous prime is 405685867. The next prime is 405685921. The reversal of 405685891 is 198586504.

It is a cyclic number.

It is not a de Polignac number, because 405685891 - 2⁵ = 405685859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (405685831) 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, 30025 + ... + 41386.

It is an arithmetic number, because the mean of its divisors is an integer number (29993040).

Almost surely, 2^405685891 is an apocalyptic number.

405685891 is a deficient number, since it is larger than the sum of its proper divisors (74202749).

405685891 is a wasteful number, since it uses less digits than its factorization.

405685891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71466.

The product of its (nonzero) digits is 345600, while the sum is 46.

The square root of 405685891 is about 20141.6456874805. The cubic root of 405685891 is about 740.2810540644.

The spelling of 405685891 in words is "four hundred five million, six hundred eighty-five thousand, eight hundred ninety-one".