21064563185 has 4 divisors (see below), whose sum is σ = 25277475828. Its totient is φ = 16851650544.

The previous prime is 21064563097. The next prime is 21064563241. The reversal of 21064563185 is 58136546012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11085352369 + 9979210816 = 105287^2 + 99896^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21064563185 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2106456314 + ... + 2106456323.

It is an arithmetic number, because the mean of its divisors is an integer number (6319368957).

Almost surely, 2^21064563185 is an apocalyptic number.

It is an amenable number.

21064563185 is a deficient number, since it is larger than the sum of its proper divisors (4212912643).

21064563185 is an equidigital number, since it uses as much as digits as its factorization.

21064563185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4212912642.

The product of its (nonzero) digits is 172800, while the sum is 41.

The spelling of 21064563185 in words is "twenty-one billion, sixty-four million, five hundred sixty-three thousand, one hundred eighty-five".