20845520640 has 576 divisors, whose sum is σ = 85161216000. Its totient is φ = 4729798656.

The previous prime is 20845520623. The next prime is 20845520651. The reversal of 20845520640 is 4602554802.

It is a happy number.

20845520640 is a `hidden beast` number, since 2 + 0 + 8 + 4 + 5 + 5 + 2 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20845520595 and 20845520604.

It is a congruent number.

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 63 ways as a sum of consecutive naturals, for example, 48141864 + ... + 48142296.

Almost surely, 2^20845520640 is an apocalyptic number.

20845520640 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 20845520640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42580608000).

20845520640 is an abundant number, since it is smaller than the sum of its proper divisors (64315695360).

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

20845520640 is a wasteful number, since it uses less digits than its factorization.

20845520640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669 (or 649 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The spelling of 20845520640 in words is "twenty billion, eight hundred forty-five million, five hundred twenty thousand, six hundred forty".