21782405898 has 128 divisors (see below), whose sum is σ = 58343639040. Its totient is φ = 5942280960.

The previous prime is 21782405891. The next prime is 21782405899. The reversal of 21782405898 is 89850428712.

21782405898 is a `hidden beast` number, since 2 + 17 + 8 + 2 + 40 + 589 + 8 = 666.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21782405891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 185361 + ... + 279147.

It is an arithmetic number, because the mean of its divisors is an integer number (455809680).

Almost surely, 2^21782405898 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21782405898, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29171819520).

21782405898 is an abundant number, since it is smaller than the sum of its proper divisors (36561233142).

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

21782405898 is a wasteful number, since it uses less digits than its factorization.

21782405898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93849 (or 93843 counting only the distinct ones).

The product of its (nonzero) digits is 2580480, while the sum is 54.

The spelling of 21782405898 in words is "twenty-one billion, seven hundred eighty-two million, four hundred five thousand, eight hundred ninety-eight".