21385057585 has 8 divisors (see below), whose sum is σ = 25663225896. Its totient is φ = 17107274880.

The previous prime is 21385057583. The next prime is 21385057613. The reversal of 21385057585 is 58575058312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 162103824 + 21222953761 = 12732^2 + 145681^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21385057585 - 2¹ = 21385057583 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21385057583) 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 7 ways as a sum of consecutive naturals, for example, 44275 + ... + 211495.

It is an arithmetic number, because the mean of its divisors is an integer number (3207903237).

Almost surely, 2^21385057585 is an apocalyptic number.

It is an amenable number.

21385057585 is a deficient number, since it is larger than the sum of its proper divisors (4278168311).

21385057585 is a wasteful number, since it uses less digits than its factorization.

21385057585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192803.

The product of its (nonzero) digits is 1680000, while the sum is 49.

The spelling of 21385057585 in words is "twenty-one billion, three hundred eighty-five million, fifty-seven thousand, five hundred eighty-five".