20503534644 has 192 divisors, whose sum is σ = 57609216000. Its totient is φ = 6286896000.

The previous prime is 20503534637. The next prime is 20503534663. The reversal of 20503534644 is 44643530502.

20503534644 is a `hidden beast` number, since 2 + 0 + 5 + 0 + 3 + 5 + 3 + 4 + 644 = 666.

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 = 20503534599 and 20503534608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 27301269 + ... + 27302019.

It is an arithmetic number, because the mean of its divisors is an integer number (300048000).

Almost surely, 2^20503534644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20503534644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28804608000).

20503534644 is an abundant number, since it is smaller than the sum of its proper divisors (37105681356).

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

20503534644 is a wasteful number, since it uses less digits than its factorization.

20503534644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1195 (or 1187 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 36.

The spelling of 20503534644 in words is "twenty billion, five hundred three million, five hundred thirty-four thousand, six hundred forty-four".