20664939600 has 270 divisors, whose sum is σ = 75690864366. Its totient is φ = 5220288000.

The previous prime is 20664939587. The next prime is 20664939629. The reversal of 20664939600 is 693946602.

20664939600 is a `hidden beast` number, since 2 + 0 + 6 + 6 + 4 + 9 + 39 + 600 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 6662477376 + 14002462224 = 81624^2 + 118332^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 1291650 + ... + 1307550.

Almost surely, 2^20664939600 is an apocalyptic number.

20664939600 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 20664939600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37845432183).

20664939600 is an abundant number, since it is smaller than the sum of its proper divisors (55025924766).

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

20664939600 is a wasteful number, since it uses less digits than its factorization.

20664939600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15963 (or 15930 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 45.

The spelling of 20664939600 in words is "twenty billion, six hundred sixty-four million, nine hundred thirty-nine thousand, six hundred".