21718794240 has 768 divisors, whose sum is σ = 89312146560. Its totient is φ = 4812963840.

The previous prime is 21718794221. The next prime is 21718794241. The reversal of 21718794240 is 4249781712.

21718794240 is a `hidden beast` number, since 217 + 1 + 8 + 7 + 9 + 424 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (768).

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

It is not an unprimeable number, because it can be changed into a prime (21718794241) 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, 210862029 + ... + 210862131.

Almost surely, 2^21718794240 is an apocalyptic number.

21718794240 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 21718794240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44656073280).

21718794240 is an abundant number, since it is smaller than the sum of its proper divisors (67593352320).

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

21718794240 is a wasteful number, since it uses less digits than its factorization.

21718794240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The spelling of 21718794240 in words is "twenty-one billion, seven hundred eighteen million, seven hundred ninety-four thousand, two hundred forty".