21064087428 has 12 divisors (see below), whose sum is σ = 49149537360. Its totient is φ = 7021362472.

The previous prime is 21064087411. The next prime is 21064087441. The reversal of 21064087428 is 82478046012.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 21064087428.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 877670298 + ... + 877670321.

It is an arithmetic number, because the mean of its divisors is an integer number (4095794780).

Almost surely, 2^21064087428 is an apocalyptic number.

It is an amenable number.

21064087428 is an abundant number, since it is smaller than the sum of its proper divisors (28085449932).

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

21064087428 is a wasteful number, since it uses less digits than its factorization.

21064087428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1755340626 (or 1755340624 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 42.

The spelling of 21064087428 in words is "twenty-one billion, sixty-four million, eighty-seven thousand, four hundred twenty-eight".