20857805768 has 12 divisors (see below), whose sum is σ = 39109151745. Its totient is φ = 10428698640.

The previous prime is 20857805753. The next prime is 20857805777. The reversal of 20857805768 is 86750875802.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 12887244484 + 7970561284 = 113522^2 + 89278^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=102122.

It is a super-2 number, since 2×20857805768² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 2 ways as a sum of consecutive naturals, for example, 382958 + ... + 434018.

Almost surely, 2^20857805768 is an apocalyptic number.

It is an amenable number.

20857805768 is a deficient number, since it is larger than the sum of its proper divisors (18251345977).

20857805768 is an frugal number, since it uses more digits than its factorization.

20857805768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102128 (or 51063 counting only the distinct ones).

The product of its (nonzero) digits is 7526400, while the sum is 56.

The spelling of 20857805768 in words is "twenty billion, eight hundred fifty-seven million, eight hundred five thousand, seven hundred sixty-eight".