21064575408 has 40 divisors (see below), whose sum is σ = 54446896128. Its totient is φ = 7017644352.

The previous prime is 21064575403. The next prime is 21064575439. The reversal of 21064575408 is 80457546012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21064575408.

It is not an unprimeable number, because it can be changed into a prime (21064575403) by changing a digit.

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, 32860 + ... + 207867.

Almost surely, 2^21064575408 is an apocalyptic number.

It is an amenable number.

21064575408 is an abundant number, since it is smaller than the sum of its proper divisors (33382320720).

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

21064575408 is a wasteful number, since it uses less digits than its factorization.

21064575408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242561 (or 242555 counting only the distinct ones).

The product of its (nonzero) digits is 268800, while the sum is 42.

The spelling of 21064575408 in words is "twenty-one billion, sixty-four million, five hundred seventy-five thousand, four hundred eight".