21021320330 has 16 divisors (see below), whose sum is σ = 38761264584. Its totient is φ = 8203441920.

The previous prime is 21021320297. The next prime is 21021320357. The reversal of 21021320330 is 3302312012.

It can be written as a sum of positive squares in 4 ways, for example, as 17811304681 + 3210015649 = 133459^2 + 56657^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21021320299 and 21021320308.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25635347 + ... + 25636166.

Almost surely, 2^21021320330 is an apocalyptic number.

21021320330 is a deficient number, since it is larger than the sum of its proper divisors (17739944254).

21021320330 is a wasteful number, since it uses less digits than its factorization.

21021320330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51271561.

The product of its (nonzero) digits is 216, while the sum is 17.

Adding to 21021320330 its reverse (3302312012), we get a palindrome (24323632342).

The spelling of 21021320330 in words is "twenty-one billion, twenty-one million, three hundred twenty thousand, three hundred thirty".