21105520355005 has 8 divisors (see below), whose sum is σ = 25437221040600. Its totient is φ = 16810685207616.

The previous prime is 21105520354979. The next prime is 21105520355011. The reversal of 21105520355005 is 50055302550112.

It can be written as a sum of positive squares in 4 ways, for example, as 5455125455641 + 15650394899364 = 2335621^2 + 3956058^2 .

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 21105520355005 - 2⁵ = 21105520354973 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9216383290 + ... + 9216385579.

It is an arithmetic number, because the mean of its divisors is an integer number (3179652630075).

Almost surely, 2^{21105520355005} is an apocalyptic number.

It is an amenable number.

21105520355005 is a deficient number, since it is larger than the sum of its proper divisors (4331700685595).

21105520355005 is a wasteful number, since it uses less digits than its factorization.

21105520355005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18432769103.

The product of its (nonzero) digits is 37500, while the sum is 34.

The spelling of 21105520355005 in words is "twenty-one trillion, one hundred five billion, five hundred twenty million, three hundred fifty-five thousand, five".