21520667025173 has 8 divisors (see below), whose sum is σ = 22188307877592. Its totient is φ = 20857552551936.

The previous prime is 21520667025139. The next prime is 21520667025229. The reversal of 21520667025173 is 37152076602512.

It can be written as a sum of positive squares in 4 ways, for example, as 6899694732529 + 14620972292644 = 2626727^2 + 3823738^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21520667025173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520667225173) 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, 1131585140 + ... + 1131604157.

It is an arithmetic number, because the mean of its divisors is an integer number (2773538484699).

Almost surely, 2^{21520667025173} is an apocalyptic number.

It is an amenable number.

21520667025173 is a deficient number, since it is larger than the sum of its proper divisors (667640852419).

21520667025173 is a wasteful number, since it uses less digits than its factorization.

21520667025173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2263189591.

The product of its (nonzero) digits is 1058400, while the sum is 47.

The spelling of 21520667025173 in words is "twenty-one trillion, five hundred twenty billion, six hundred sixty-seven million, twenty-five thousand, one hundred seventy-three".