20428405806 has 16 divisors (see below), whose sum is σ = 40949884800. Its totient is φ = 6793956408.

The previous prime is 20428405771. The next prime is 20428405813. The reversal of 20428405806 is 60850482402.

It is a super-4 number, since 4×20428405806⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3875196 + ... + 3880463.

It is an arithmetic number, because the mean of its divisors is an integer number (2559367800).

Almost surely, 2^20428405806 is an apocalyptic number.

20428405806 is an abundant number, since it is smaller than the sum of its proper divisors (20521478994).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20428405806 is a wasteful number, since it uses less digits than its factorization.

20428405806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7756103.

The product of its (nonzero) digits is 122880, while the sum is 39.

The spelling of 20428405806 in words is "twenty billion, four hundred twenty-eight million, four hundred five thousand, eight hundred six".