21021303040 has 72 divisors (see below), whose sum is σ = 50497939800. Its totient is φ = 8384249856.

The previous prime is 21021302971. The next prime is 21021303041. The reversal of 21021303040 is 4030312012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 524226816 + 20497076224 = 22896^2 + 143168^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (21021303041) 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, 423192 + ... + 470248.

It is an arithmetic number, because the mean of its divisors is an integer number (701360275).

Almost surely, 2^21021303040 is an apocalyptic number.

21021303040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021303040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25248969900).

21021303040 is an abundant number, since it is smaller than the sum of its proper divisors (29476636760).

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

21021303040 is an equidigital number, since it uses as much as digits as its factorization.

21021303040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47427 (or 47413 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21021303040 its reverse (4030312012), we get a palindrome (25051615052).

The spelling of 21021303040 in words is "twenty-one billion, twenty-one million, three hundred three thousand, forty".