20945639520 has 288 divisors, whose sum is σ = 81027928800. Its totient is φ = 4884406272.

The previous prime is 20945639503. The next prime is 20945639543. The reversal of 20945639520 is 2593654902.

20945639520 is a `hidden beast` number, since 2 + 0 + 9 + 4 + 5 + 639 + 5 + 2 + 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 an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 326236 + ... + 385124.

It is an arithmetic number, because the mean of its divisors is an integer number (281346975).

Almost surely, 2^20945639520 is an apocalyptic number.

20945639520 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 20945639520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40513964400).

20945639520 is an abundant number, since it is smaller than the sum of its proper divisors (60082289280).

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

20945639520 is a wasteful number, since it uses less digits than its factorization.

20945639520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58942 (or 58931 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 45.

The spelling of 20945639520 in words is "twenty billion, nine hundred forty-five million, six hundred thirty-nine thousand, five hundred twenty".