20857680511 has 4 divisors (see below), whose sum is σ = 22084602912. Its totient is φ = 19630758112.

The previous prime is 20857680497. The next prime is 20857680551. The reversal of 20857680511 is 11508675802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20857680511 - 2²⁵ = 20824126079 is a prime.

It is a super-3 number, since 3×20857680511³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20857680551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 613461175 + ... + 613461208.

It is an arithmetic number, because the mean of its divisors is an integer number (5521150728).

Almost surely, 2^20857680511 is an apocalyptic number.

20857680511 is a deficient number, since it is larger than the sum of its proper divisors (1226922401).

20857680511 is a wasteful number, since it uses less digits than its factorization.

20857680511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1226922400.

The product of its (nonzero) digits is 134400, while the sum is 43.

The spelling of 20857680511 in words is "twenty billion, eight hundred fifty-seven million, six hundred eighty thousand, five hundred eleven".