20856487686 has 16 divisors (see below), whose sum is σ = 42013070400. Its totient is φ = 6902146728.

The previous prime is 20856487681. The next prime is 20856487727. The reversal of 20856487686 is 68678465802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20856487681) 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, 12503056 + ... + 12504723.

It is an arithmetic number, because the mean of its divisors is an integer number (2625816900).

Almost surely, 2^20856487686 is an apocalyptic number.

20856487686 is an abundant number, since it is smaller than the sum of its proper divisors (21156582714).

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

20856487686 is a wasteful number, since it uses less digits than its factorization.

20856487686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25007923.

The product of its (nonzero) digits is 30965760, while the sum is 60.

The spelling of 20856487686 in words is "twenty billion, eight hundred fifty-six million, four hundred eighty-seven thousand, six hundred eighty-six".