21208813575 has 24 divisors (see below), whose sum is σ = 35077161168. Its totient is φ = 11307521280.

The previous prime is 21208813541. The next prime is 21208813601. The reversal of 21208813575 is 57531880212.

It is not a de Polignac number, because 21208813575 - 2¹⁵ = 21208780807 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 181219 + ... + 274331.

It is an arithmetic number, because the mean of its divisors is an integer number (1461548382).

Almost surely, 2^21208813575 is an apocalyptic number.

21208813575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21208813575 is a deficient number, since it is larger than the sum of its proper divisors (13868347593).

21208813575 is a wasteful number, since it uses less digits than its factorization.

21208813575 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96163 (or 96158 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 42.

The spelling of 21208813575 in words is "twenty-one billion, two hundred eight million, eight hundred thirteen thousand, five hundred seventy-five".