21765445632 has 576 divisors, whose sum is σ = 77867244000. Its totient is φ = 5982584832.

The previous prime is 21765445591. The next prime is 21765445643. The reversal of 21765445632 is 23654456712.

21765445632 is a `hidden beast` number, since 2 + 1 + 7 + 6 + 5 + 4 + 4 + 5 + 632 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 78575478 + ... + 78575754.

Almost surely, 2^21765445632 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 21765445632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38933622000).

21765445632 is an abundant number, since it is smaller than the sum of its proper divisors (56101798368).

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

21765445632 is a wasteful number, since it uses less digits than its factorization.

21765445632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351 (or 318 counting only the distinct ones).

The product of its digits is 1209600, while the sum is 45.

The spelling of 21765445632 in words is "twenty-one billion, seven hundred sixty-five million, four hundred forty-five thousand, six hundred thirty-two".