21023305540 has 48 divisors (see below), whose sum is σ = 44614072944. Its totient is φ = 8320832000.

The previous prime is 21023305529. The next prime is 21023305543. The reversal of 21023305540 is 4550332012.

It can be written as a sum of positive squares in 8 ways, for example, as 986336836 + 20036968704 = 31406^2 + 141552^2 .

It is not an unprimeable number, because it can be changed into a prime (21023305543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5534922 + ... + 5538718.

It is an arithmetic number, because the mean of its divisors is an integer number (929459853).

Almost surely, 2^21023305540 is an apocalyptic number.

21023305540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21023305540 is an abundant number, since it is smaller than the sum of its proper divisors (23590767404).

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

21023305540 is a wasteful number, since it uses less digits than its factorization.

21023305540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6648 (or 6646 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 25.

Adding to 21023305540 its reverse (4550332012), we get a palindrome (25573637552).

The spelling of 21023305540 in words is "twenty-one billion, twenty-three million, three hundred five thousand, five hundred forty".