21305002000 has 40 divisors (see below), whose sum is σ = 51515499672. Its totient is φ = 8522000000.

The previous prime is 21305001997. The next prime is 21305002001. The reversal of 21305002000 is 20050312.

It can be written as a sum of positive squares in 4 ways, for example, as 6016174096 + 15288827904 = 77564^2 + 123648^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×21305002000² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21305002001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5324251 + ... + 5328250.

Almost surely, 2^21305002000 is an apocalyptic number.

21305002000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21305002000 is an abundant number, since it is smaller than the sum of its proper divisors (30210497672).

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

21305002000 is a wasteful number, since it uses less digits than its factorization.

21305002000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10652524 (or 10652508 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 13.

Adding to 21305002000 its reverse (20050312), we get a palindrome (21325052312).

The spelling of 21305002000 in words is "twenty-one billion, three hundred five million, two thousand".