21787605504 has 560 divisors, whose sum is σ = 77285767680. Its totient is φ = 6001827840.

The previous prime is 21787605487. The next prime is 21787605517. The reversal of 21787605504 is 40550678712.

21787605504 is a `hidden beast` number, since 2 + 1 + 7 + 87 + 60 + 5 + 504 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21787605504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 80994682 + ... + 80994950.

Almost surely, 2^21787605504 is an apocalyptic number.

21787605504 is a gapful number since it is divisible by the number (24) 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 21787605504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38642883840).

21787605504 is an abundant number, since it is smaller than the sum of its proper divisors (55498162176).

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

21787605504 is an frugal number, since it uses more digits than its factorization.

21787605504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 45.

The spelling of 21787605504 in words is "twenty-one billion, seven hundred eighty-seven million, six hundred five thousand, five hundred four".