20866782600 has 360 divisors, whose sum is σ = 77004616590. Its totient is φ = 5235978240.

The previous prime is 20866782593. The next prime is 20866782647. The reversal of 20866782600 is 628766802.

It is a happy number.

It can be written as a sum of positive squares in 9 ways, for example, as 7649601444 + 13217181156 = 87462^2 + 114966^2 .

It is a tau number, because it is divible by the number of its divisors (360).

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

It is an unprimeable number.

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 89 ways as a sum of consecutive naturals, for example, 4679572 + ... + 4684028.

Almost surely, 2^20866782600 is an apocalyptic number.

20866782600 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 20866782600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38502308295).

20866782600 is an abundant number, since it is smaller than the sum of its proper divisors (56137833990).

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

20866782600 is a wasteful number, since it uses less digits than its factorization.

20866782600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4519 (or 4484 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The spelling of 20866782600 in words is "twenty billion, eight hundred sixty-six million, seven hundred eighty-two thousand, six hundred".