21542304020 has 12 divisors (see below), whose sum is σ = 45238838484. Its totient is φ = 8616921600.

The previous prime is 21542304013. The next prime is 21542304029. The reversal of 21542304020 is 2040324512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 15518681476 + 6023622544 = 124574^2 + 77612^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21542304029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 538557581 + ... + 538557620.

It is an arithmetic number, because the mean of its divisors is an integer number (3769903207).

Almost surely, 2^21542304020 is an apocalyptic number.

21542304020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21542304020 is an abundant number, since it is smaller than the sum of its proper divisors (23696534464).

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

21542304020 is a wasteful number, since it uses less digits than its factorization.

21542304020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1077115210 (or 1077115208 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

Adding to 21542304020 its reverse (2040324512), we get a palindrome (23582628532).

The spelling of 21542304020 in words is "twenty-one billion, five hundred forty-two million, three hundred four thousand, twenty".