21543042040 has 64 divisors (see below), whose sum is σ = 53884373760. Its totient is φ = 7697756160.

The previous prime is 21543041969. The next prime is 21543042043. The reversal of 21543042040 is 4024034512.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21543041996 and 21543042014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21543042043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 652089 + ... + 684328.

It is an arithmetic number, because the mean of its divisors is an integer number (841943340).

Almost surely, 2^21543042040 is an apocalyptic number.

21543042040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21543042040 is an abundant number, since it is smaller than the sum of its proper divisors (32341331720).

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

21543042040 is a wasteful number, since it uses less digits than its factorization.

21543042040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1336472 (or 1336468 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 21543042040 its reverse (4024034512), we get a palindrome (25567076552).

The spelling of 21543042040 in words is "twenty-one billion, five hundred forty-three million, forty-two thousand, forty".