20535584640 has 128 divisors (see below), whose sum is σ = 65588896800. Its totient is φ = 5465137152.

The previous prime is 20535584609. The next prime is 20535584647. The reversal of 20535584640 is 4648553502.

It is a tau number, because it is divible by the number of its divisors (128).

It is a junction number, because it is equal to n+sod(n) for n = 20535584592 and 20535584601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20535584647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 966774 + ... + 987786.

Almost surely, 2^20535584640 is an apocalyptic number.

20535584640 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 20535584640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32794448400).

20535584640 is an abundant number, since it is smaller than the sum of its proper divisors (45053312160).

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

20535584640 is a wasteful number, since it uses less digits than its factorization.

20535584640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21544 (or 21532 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 42.

The spelling of 20535584640 in words is "twenty billion, five hundred thirty-five million, five hundred eighty-four thousand, six hundred forty".