20639335680 has 288 divisors, whose sum is σ = 73436832000. Its totient is φ = 5489123328.

The previous prime is 20639335621. The next prime is 20639335681. The reversal of 20639335680 is 8653393602.

20639335680 is a `hidden beast` number, since 2 + 0 + 639 + 3 + 3 + 5 + 6 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20639335681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20700942 + ... + 20701938.

It is an arithmetic number, because the mean of its divisors is an integer number (254989000).

Almost surely, 2^20639335680 is an apocalyptic number.

20639335680 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 20639335680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36718416000).

20639335680 is an abundant number, since it is smaller than the sum of its proper divisors (52797496320).

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

20639335680 is an equidigital number, since it uses as much as digits as its factorization.

20639335680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1626 (or 1606 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 45.

The spelling of 20639335680 in words is "twenty billion, six hundred thirty-nine million, three hundred thirty-five thousand, six hundred eighty".