20857871838 has 16 divisors (see below), whose sum is σ = 41748426000. Its totient is φ = 6947176896.

The previous prime is 20857871831. The next prime is 20857871873. The reversal of 20857871838 is 83817875802.

It is a super-2 number, since 2×20857871838² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20857871831) 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 7 ways as a sum of consecutive naturals, for example, 1353463 + ... + 1368786.

It is an arithmetic number, because the mean of its divisors is an integer number (2609276625).

Almost surely, 2^20857871838 is an apocalyptic number.

20857871838 is an abundant number, since it is smaller than the sum of its proper divisors (20890554162).

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

20857871838 is a wasteful number, since it uses less digits than its factorization.

20857871838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2723531.

The product of its (nonzero) digits is 6021120, while the sum is 57.

The spelling of 20857871838 in words is "twenty billion, eight hundred fifty-seven million, eight hundred seventy-one thousand, eight hundred thirty-eight".