21004240554 has 192 divisors, whose sum is σ = 53714119680. Its totient is φ = 5861184000.

The previous prime is 21004240541. The next prime is 21004240559. The reversal of 21004240554 is 45504240012.

21004240554 is a `hidden beast` number, since 2 + 100 + 4 + 2 + 4 + 0 + 554 = 666.

It is not an unprimeable number, because it can be changed into a prime (21004240559) 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 95 ways as a sum of consecutive naturals, for example, 42778249 + ... + 42778739.

It is an arithmetic number, because the mean of its divisors is an integer number (279761040).

Almost surely, 2^21004240554 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21004240554, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26857059840).

21004240554 is an abundant number, since it is smaller than the sum of its proper divisors (32709879126).

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

21004240554 is a wasteful number, since it uses less digits than its factorization.

21004240554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 777 (or 774 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 27.

Adding to 21004240554 its reverse (45504240012), we get a palindrome (66508480566).

The spelling of 21004240554 in words is "twenty-one billion, four million, two hundred forty thousand, five hundred fifty-four".