21415304240 has 80 divisors (see below), whose sum is σ = 54409017600. Its totient is φ = 7774191360.

The previous prime is 21415304227. The next prime is 21415304293. The reversal of 21415304240 is 4240351412.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 506807 + ... + 547433.

It is an arithmetic number, because the mean of its divisors is an integer number (680112720).

Almost surely, 2^21415304240 is an apocalyptic number.

21415304240 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 21415304240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27204508800).

21415304240 is an abundant number, since it is smaller than the sum of its proper divisors (32993713360).

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

21415304240 is a wasteful number, since it uses less digits than its factorization.

21415304240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41250 (or 41244 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21415304240 its reverse (4240351412), we get a palindrome (25655655652).

The spelling of 21415304240 in words is "twenty-one billion, four hundred fifteen million, three hundred four thousand, two hundred forty".