21020440524 has 24 divisors (see below), whose sum is σ = 49053028080. Its totient is φ = 7006051584.

The previous prime is 21020440523. The next prime is 21020440579. The reversal of 21020440524 is 42504402012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21020440494 and 21020440503.

It is not an unprimeable number, because it can be changed into a prime (21020440523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25872 + ... + 206664.

It is an arithmetic number, because the mean of its divisors is an integer number (2043876170).

Almost surely, 2^21020440524 is an apocalyptic number.

It is an amenable number.

21020440524 is an abundant number, since it is smaller than the sum of its proper divisors (28032587556).

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

21020440524 is a wasteful number, since it uses less digits than its factorization.

21020440524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190489 (or 190487 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 24.

Adding to 21020440524 its reverse (42504402012), we get a palindrome (63524842536).

The spelling of 21020440524 in words is "twenty-one billion, twenty million, four hundred forty thousand, five hundred twenty-four".