20975728900 has 81 divisors (see below), whose sum is σ = 52974336639. Its totient is φ = 7188202560.

The previous prime is 20975728877. The next prime is 20975728901. The reversal of 20975728900 is 982757902.

The square root of 20975728900 is 144830.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 5184288004 + 15791440896 = 72002^2 + 125664^2 .

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (20975728901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 10137066 + ... + 10139134.

Almost surely, 2^20975728900 is an apocalyptic number.

20975728900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

20975728900 is the 144830-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20975728900

20975728900 is an abundant number, since it is smaller than the sum of its proper divisors (31998607739).

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

20975728900 is an equidigital number, since it uses as much as digits as its factorization.

20975728900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4166 (or 2083 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 49.

Multiplying 20975728900 by its sum of digits (49), we get a square (1027810716100 = 1013810²).

20975728900 divided by its sum of digits (49) gives a square (428076100 = 20690²).

The spelling of 20975728900 in words is "twenty billion, nine hundred seventy-five million, seven hundred twenty-eight thousand, nine hundred".