20556720000 has 640 divisors, whose sum is σ = 78514867200. Its totient is φ = 5287680000.

The previous prime is 20556719971. The next prime is 20556720011. The reversal of 20556720000 is 2765502.

It is a tau number, because it is divible by the number of its divisors (640).

It is a super-3 number, since 3×20556720000³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 66959847 + ... + 66960153.

It is an arithmetic number, because the mean of its divisors is an integer number (122679480).

Almost surely, 2^20556720000 is an apocalyptic number.

20556720000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20556720000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39257433600).

20556720000 is an abundant number, since it is smaller than the sum of its proper divisors (57958147200).

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

20556720000 is an equidigital number, since it uses as much as digits as its factorization.

20556720000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381 (or 348 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The spelling of 20556720000 in words is "twenty billion, five hundred fifty-six million, seven hundred twenty thousand".