21788605440 has 528 divisors, whose sum is σ = 89106401280. Its totient is φ = 4817387520.

The previous prime is 21788605429. The next prime is 21788605453. The reversal of 21788605440 is 4450688712.

21788605440 is a `hidden beast` number, since 21 + 7 + 8 + 86 + 0 + 544 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 9998271 + ... + 10000449.

Almost surely, 2^21788605440 is an apocalyptic number.

21788605440 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 21788605440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44553200640).

21788605440 is an abundant number, since it is smaller than the sum of its proper divisors (67317795840).

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

21788605440 is a wasteful number, since it uses less digits than its factorization.

21788605440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2248 (or 2227 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

The spelling of 21788605440 in words is "twenty-one billion, seven hundred eighty-eight million, six hundred five thousand, four hundred forty".