21531355330325 has 24 divisors (see below), whose sum is σ = 27039960847368. Its totient is φ = 17006218772480.

The previous prime is 21531355330319. The next prime is 21531355330343. The reversal of 21531355330325 is 52303355313512.

It can be written as a sum of positive squares in 12 ways, for example, as 6800443510756 + 14730911819569 = 2607766^2 + 3838087^2 .

It is not a de Polignac number, because 21531355330325 - 2²⁶ = 21531288221461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14102222 + ... + 15554271.

It is an arithmetic number, because the mean of its divisors is an integer number (1126665035307).

Almost surely, 2^{21531355330325} is an apocalyptic number.

21531355330325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21531355330325 is a deficient number, since it is larger than the sum of its proper divisors (5508605517043).

21531355330325 is a wasteful number, since it uses less digits than its factorization.

21531355330325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29656873 (or 29656868 counting only the distinct ones).

The product of its (nonzero) digits is 607500, while the sum is 41.

The spelling of 21531355330325 in words is "twenty-one trillion, five hundred thirty-one billion, three hundred fifty-five million, three hundred thirty thousand, three hundred twenty-five".