21213612523853 has 2 divisors, whose sum is σ = 21213612523854. Its totient is φ = 21213612523852.

The previous prime is 21213612523837. The next prime is 21213612523867. The reversal of 21213612523853 is 35832521631212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11692549396969 + 9521063126884 = 3419437^2 + 3085622^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213612523853 - 2⁴ = 21213612523837 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213612523253) 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 as a sum of consecutive naturals, namely, 10606806261926 + 10606806261927.

It is an arithmetic number, because the mean of its divisors is an integer number (10606806261927).

Almost surely, 2^{21213612523853} is an apocalyptic number.

It is an amenable number.

21213612523853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213612523853 is an equidigital number, since it uses as much as digits as its factorization.

21213612523853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 518400, while the sum is 44.

The spelling of 21213612523853 in words is "twenty-one trillion, two hundred thirteen billion, six hundred twelve million, five hundred twenty-three thousand, eight hundred fifty-three".