20851728570 has 48 divisors (see below), whose sum is σ = 54222491232. Its totient is φ = 5559640800.

The previous prime is 20851728551. The next prime is 20851728571. The reversal of 20851728570 is 7582715802.

20851728570 is a `hidden beast` number, since 2 + 0 + 8 + 5 + 1 + 72 + 8 + 570 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (20851728571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 826645 + ... + 851495.

It is an arithmetic number, because the mean of its divisors is an integer number (1129635234).

Almost surely, 2^20851728570 is an apocalyptic number.

20851728570 is an abundant number, since it is smaller than the sum of its proper divisors (33370762662).

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

20851728570 is a wasteful number, since it uses less digits than its factorization.

20851728570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34187 (or 34184 counting only the distinct ones).

The product of its (nonzero) digits is 313600, while the sum is 45.

The spelling of 20851728570 in words is "twenty billion, eight hundred fifty-one million, seven hundred twenty-eight thousand, five hundred seventy".