21240313040 has 40 divisors (see below), whose sum is σ = 49418552040. Its totient is φ = 8490134016.

The previous prime is 21240313021. The next prime is 21240313049. The reversal of 21240313040 is 4031304212.

It can be written as a sum of positive squares in 4 ways, for example, as 3839537296 + 17400775744 = 61964^2 + 131912^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240313049) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21422 + ... + 207218.

It is an arithmetic number, because the mean of its divisors is an integer number (1235463801).

Almost surely, 2^21240313040 is an apocalyptic number.

21240313040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21240313040 is an abundant number, since it is smaller than the sum of its proper divisors (28178239000).

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

21240313040 is a wasteful number, since it uses less digits than its factorization.

21240313040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187239 (or 187233 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21240313040 its reverse (4031304212), we get a palindrome (25271617252).

The spelling of 21240313040 in words is "twenty-one billion, two hundred forty million, three hundred thirteen thousand, forty".