21064680021 has 24 divisors (see below), whose sum is σ = 35641910304. Its totient is φ = 10942690080.

The previous prime is 21064679983. The next prime is 21064680037. The reversal of 21064680021 is 12008646012.

It is not a de Polignac number, because 21064680021 - 2¹¹ = 21064677973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064680061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6511890 + ... + 6515123.

It is an arithmetic number, because the mean of its divisors is an integer number (1485079596).

Almost surely, 2^21064680021 is an apocalyptic number.

21064680021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21064680021 is a deficient number, since it is larger than the sum of its proper divisors (14577230283).

21064680021 is a wasteful number, since it uses less digits than its factorization.

21064680021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13027041 (or 13027034 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The spelling of 21064680021 in words is "twenty-one billion, sixty-four million, six hundred eighty thousand, twenty-one".