21042223540 has 96 divisors (see below), whose sum is σ = 48413191680. Its totient is φ = 7635603456.

The previous prime is 21042223529. The next prime is 21042223549. The reversal of 21042223540 is 4532224012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042223549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4660324 + ... + 4664836.

It is an arithmetic number, because the mean of its divisors is an integer number (504304080).

Almost surely, 2^21042223540 is an apocalyptic number.

21042223540 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 21042223540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24206595840).

21042223540 is an abundant number, since it is smaller than the sum of its proper divisors (27370968140).

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

21042223540 is a wasteful number, since it uses less digits than its factorization.

21042223540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4841 (or 4839 counting only the distinct ones).

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

Adding to 21042223540 its reverse (4532224012), we get a palindrome (25574447552).

The spelling of 21042223540 in words is "twenty-one billion, forty-two million, two hundred twenty-three thousand, five hundred forty".