21520445752213 has 8 divisors (see below), whose sum is σ = 21574307977560. Its totient is φ = 21466584499200.

The previous prime is 21520445752177. The next prime is 21520445752291. The reversal of 21520445752213 is 31225754402512.

It can be written as a sum of positive squares in 4 ways, for example, as 6323102518084 + 15197343234129 = 2514578^2 + 3898377^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21520445752213 - 2¹⁷ = 21520445621141 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 21520445752213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520445756213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67975581 + ... + 68291437.

It is an arithmetic number, because the mean of its divisors is an integer number (2696788497195).

Almost surely, 2^{21520445752213} is an apocalyptic number.

It is an amenable number.

21520445752213 is a deficient number, since it is larger than the sum of its proper divisors (53862225347).

21520445752213 is a wasteful number, since it uses less digits than its factorization.

21520445752213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486167.

The product of its (nonzero) digits is 672000, while the sum is 43.

The spelling of 21520445752213 in words is "twenty-one trillion, five hundred twenty billion, four hundred forty-five million, seven hundred fifty-two thousand, two hundred thirteen".