21512512305211 has 4 divisors (see below), whose sum is σ = 21865176441424. Its totient is φ = 21159848169000.

The previous prime is 21512512305209. The next prime is 21512512305233. The reversal of 21512512305211 is 11250321521512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21512512305211 - 2¹ = 21512512305209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21512512305311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 176332068015 + ... + 176332068136.

It is an arithmetic number, because the mean of its divisors is an integer number (5466294110356).

Almost surely, 2^{21512512305211} is an apocalyptic number.

21512512305211 is a deficient number, since it is larger than the sum of its proper divisors (352664136213).

21512512305211 is an equidigital number, since it uses as much as digits as its factorization.

21512512305211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352664136212.

The product of its (nonzero) digits is 6000, while the sum is 31.

Adding to 21512512305211 its reverse (11250321521512), we get a palindrome (32762833826723).

The spelling of 21512512305211 in words is "twenty-one trillion, five hundred twelve billion, five hundred twelve million, three hundred five thousand, two hundred eleven".