20557728320 has 28 divisors (see below), whose sum is σ = 48953091324. Its totient is φ = 8223091200.

The previous prime is 20557728263. The next prime is 20557728343. The reversal of 20557728320 is 2382775502.

It can be written as a sum of positive squares in 2 ways, for example, as 4848615424 + 15709112896 = 69632^2 + 125336^2 .

It is a super-3 number, since 3×20557728320³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32121131 + ... + 32121770.

Almost surely, 2^20557728320 is an apocalyptic number.

20557728320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20557728320 is an abundant number, since it is smaller than the sum of its proper divisors (28395363004).

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

20557728320 is an equidigital number, since it uses as much as digits as its factorization.

20557728320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64242918 (or 64242908 counting only the distinct ones).

The product of its (nonzero) digits is 235200, while the sum is 41.

The spelling of 20557728320 in words is "twenty billion, five hundred fifty-seven million, seven hundred twenty-eight thousand, three hundred twenty".