21206322452173 has 4 divisors (see below), whose sum is σ = 21209637500380. Its totient is φ = 21203007403968.

The previous prime is 21206322452129. The next prime is 21206322452221. The reversal of 21206322452173 is 37125422360212.

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 10786770999684 + 10419551452489 = 3284322^2 + 3227933^2 .

It is a cyclic number.

It is not a de Polignac number, because 21206322452173 - 2³³ = 21197732517581 is a prime.

It is a super-3 number, since 3×21206322452173³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21206322452473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1657514508 + ... + 1657527301.

It is an arithmetic number, because the mean of its divisors is an integer number (5302409375095).

Almost surely, 2^{21206322452173} is an apocalyptic number.

It is an amenable number.

21206322452173 is a deficient number, since it is larger than the sum of its proper divisors (3315048207).

21206322452173 is an equidigital number, since it uses as much as digits as its factorization.

21206322452173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3315048206.

The product of its (nonzero) digits is 241920, while the sum is 40.

The spelling of 21206322452173 in words is "twenty-one trillion, two hundred six billion, three hundred twenty-two million, four hundred fifty-two thousand, one hundred seventy-three".