21124444420 has 24 divisors (see below), whose sum is σ = 44364529944. Its totient is φ = 8449168896.

The previous prime is 21124444417. The next prime is 21124444441. The reversal of 21124444420 is 2444442112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 147456 + 21124296964 = 384^2 + 145342^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 336214 + ... + 394066.

It is an arithmetic number, because the mean of its divisors is an integer number (1848522081).

Almost surely, 2^21124444420 is an apocalyptic number.

21124444420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21124444420 is an abundant number, since it is smaller than the sum of its proper divisors (23240085524).

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

21124444420 is a wasteful number, since it uses less digits than its factorization.

21124444420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76119 (or 76117 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 28.

Adding to 21124444420 its reverse (2444442112), we get a palindrome (23568886532).

The spelling of 21124444420 in words is "twenty-one billion, one hundred twenty-four million, four hundred forty-four thousand, four hundred twenty".