20685551806 has 8 divisors (see below), whose sum is σ = 31167468864. Its totient is φ = 10296395520.

The previous prime is 20685551801. The next prime is 20685551851. The reversal of 20685551806 is 60815558602.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20685551801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23189635 + ... + 23190526.

It is an arithmetic number, because the mean of its divisors is an integer number (3895933608).

Almost surely, 2^20685551806 is an apocalyptic number.

20685551806 is a deficient number, since it is larger than the sum of its proper divisors (10481917058).

20685551806 is a wasteful number, since it uses less digits than its factorization.

20685551806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46380386.

The product of its (nonzero) digits is 576000, while the sum is 46.

The spelling of 20685551806 in words is "twenty billion, six hundred eighty-five million, five hundred fifty-one thousand, eight hundred six".