21531350513205 has 32 divisors (see below), whose sum is σ = 41222414661120. Its totient is φ = 10600049482560.

The previous prime is 21531350513177. The next prime is 21531350513209. The reversal of 21531350513205 is 50231505313512.

21531350513205 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 13 + 505 + 132 + 0 + 5 = 666.

It is not a de Polignac number, because 21531350513205 - 2¹⁹ = 21531349988917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21531350513205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531350513209) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6134286141 + ... + 6134289650.

It is an arithmetic number, because the mean of its divisors is an integer number (1288200458160).

Almost surely, 2^{21531350513205} is an apocalyptic number.

It is an amenable number.

21531350513205 is a deficient number, since it is larger than the sum of its proper divisors (19691064147915).

21531350513205 is a wasteful number, since it uses less digits than its factorization.

21531350513205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12268575818 (or 12268575812 counting only the distinct ones).

The product of its (nonzero) digits is 67500, while the sum is 36.

Adding to 21531350513205 its reverse (50231505313512), we get a palindrome (71762855826717).

The spelling of 21531350513205 in words is "twenty-one trillion, five hundred thirty-one billion, three hundred fifty million, five hundred thirteen thousand, two hundred five".