21071807573 has 4 divisors (see below), whose sum is σ = 21079327968. Its totient is φ = 21064287180.

The previous prime is 21071807531. The next prime is 21071807593. The reversal of 21071807573 is 37570817012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21071807573 - 2²⁶ = 21004698709 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21071807573.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071807593) 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 3 ways as a sum of consecutive naturals, for example, 3755993 + ... + 3761598.

It is an arithmetic number, because the mean of its divisors is an integer number (5269831992).

Almost surely, 2^21071807573 is an apocalyptic number.

It is an amenable number.

21071807573 is a deficient number, since it is larger than the sum of its proper divisors (7520395).

21071807573 is an equidigital number, since it uses as much as digits as its factorization.

21071807573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7520394.

The product of its (nonzero) digits is 82320, while the sum is 41.

The spelling of 21071807573 in words is "twenty-one billion, seventy-one million, eight hundred seven thousand, five hundred seventy-three".