21806855939590 has 16 divisors (see below), whose sum is σ = 39252913178688. Its totient is φ = 8722615156416.

The previous prime is 21806855939527. The next prime is 21806855939593. The reversal of 21806855939590 is 9593955860812.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21806855939593) 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, 15180942 + ... + 16555201.

It is an arithmetic number, because the mean of its divisors is an integer number (2453307073668).

Almost surely, 2^{21806855939590} is an apocalyptic number.

21806855939590 is a deficient number, since it is larger than the sum of its proper divisors (17446057239098).

21806855939590 is a wasteful number, since it uses less digits than its factorization.

21806855939590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31804863.

The product of its (nonzero) digits is 209952000, while the sum is 70.

The spelling of 21806855939590 in words is "twenty-one trillion, eight hundred six billion, eight hundred fifty-five million, nine hundred thirty-nine thousand, five hundred ninety".