6561637632 has 432 divisors, whose sum is σ = 21999065088. Its totient is φ = 1933424640.

The previous prime is 6561637613. The next prime is 6561637637. The reversal of 6561637632 is 2367361656.

6561637632 is a `hidden beast` number, since 6 + 5 + 6 + 1 + 6 + 3 + 7 + 632 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561637637) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 29424273 + ... + 29424495.

Almost surely, 2^6561637632 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 6561637632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10999532544).

6561637632 is an abundant number, since it is smaller than the sum of its proper divisors (15437427456).

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

6561637632 is a wasteful number, since it uses less digits than its factorization.

6561637632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 282 counting only the distinct ones).

The product of its digits is 816480, while the sum is 45.

The square root of 6561637632 is about 81003.9359043744. The cubic root of 6561637632 is about 1872.1360847817.

The spelling of 6561637632 in words is "six billion, five hundred sixty-one million, six hundred thirty-seven thousand, six hundred thirty-two".