20857680564 has 48 divisors (see below), whose sum is σ = 55649427456.
Its totient is φ = 5956236000.
The previous prime is 20857680563. The next prime is 20857680583. The reversal of 20857680564 is 46508675802.
It is a happy number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20857680563) 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, 100249 + ... + 227519.
It is an arithmetic number, because the mean of its divisors is an integer number (1159363072).
Almost surely, 220857680564 is an apocalyptic number.
It is an amenable number.
20857680564 is an abundant number, since it is smaller than the sum of its proper divisors (34791746892).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
20857680564 is a wasteful number, since it uses less digits than its factorization.
20857680564 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 129236 (or 129234 counting only the distinct ones).
The product of its (nonzero) digits is 3225600, while the sum is 51.
The spelling of 20857680564 in words is "twenty billion, eight hundred fifty-seven million, six hundred eighty thousand, five hundred sixty-four".