21240536040 has 160 divisors (see below), whose sum is σ = 71590337280. Its totient is φ = 5648393088.

The previous prime is 21240536003. The next prime is 21240536047. The reversal of 21240536040 is 4063504212.

21240536040 is a `hidden beast` number, since 2 + 1 + 2 + 4 + 0 + 53 + 604 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21240535995 and 21240536013.

It is not an unprimeable number, because it can be changed into a prime (21240536047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1180149 + ... + 1198011.

It is an arithmetic number, because the mean of its divisors is an integer number (447439608).

Almost surely, 2^21240536040 is an apocalyptic number.

21240536040 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 21240536040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35795168640).

21240536040 is an abundant number, since it is smaller than the sum of its proper divisors (50349801240).

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

21240536040 is a wasteful number, since it uses less digits than its factorization.

21240536040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18253 (or 18240 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The spelling of 21240536040 in words is "twenty-one billion, two hundred forty million, five hundred thirty-six thousand, forty".