21055402424 has 64 divisors (see below), whose sum is σ = 45455447040. Its totient is φ = 8956552320.

The previous prime is 21055402409. The next prime is 21055402429. The reversal of 21055402424 is 42420455012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055402429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12988334 + ... + 12989954.

It is an arithmetic number, because the mean of its divisors is an integer number (710241360).

Almost surely, 2^21055402424 is an apocalyptic number.

It is an amenable number.

21055402424 is an abundant number, since it is smaller than the sum of its proper divisors (24400044616).

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

21055402424 is a wasteful number, since it uses less digits than its factorization.

21055402424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3220 (or 3216 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 29.

Adding to 21055402424 its reverse (42420455012), we get a palindrome (63475857436).

The spelling of 21055402424 in words is "twenty-one billion, fifty-five million, four hundred two thousand, four hundred twenty-four".