20857871855 has 8 divisors (see below), whose sum is σ = 25033931232. Its totient is φ = 16683307488.

The previous prime is 20857871831. The next prime is 20857871873. The reversal of 20857871855 is 55817875802.

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

It is a cyclic number.

It is not a de Polignac number, because 20857871855 - 2⁶ = 20857871791 is a prime.

It is a super-2 number, since 2×20857871855² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20857871855.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 342824 + ... + 399053.

It is an arithmetic number, because the mean of its divisors is an integer number (3129241404).

Almost surely, 2^20857871855 is an apocalyptic number.

20857871855 is a deficient number, since it is larger than the sum of its proper divisors (4176059377).

20857871855 is an equidigital number, since it uses as much as digits as its factorization.

20857871855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 747505.

The product of its (nonzero) digits is 6272000, while the sum is 56.

The spelling of 20857871855 in words is "twenty billion, eight hundred fifty-seven million, eight hundred seventy-one thousand, eight hundred fifty-five".