21001323853 has 2 divisors, whose sum is σ = 21001323854. Its totient is φ = 21001323852.

The previous prime is 21001323841. The next prime is 21001323857. The reversal of 21001323853 is 35832310012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20296846089 + 704477764 = 142467^2 + 26542^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001323853 - 2⁹ = 21001323341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001323857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500661926 + 10500661927.

It is an arithmetic number, because the mean of its divisors is an integer number (10500661927).

Almost surely, 2^21001323853 is an apocalyptic number.

It is an amenable number.

21001323853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001323853 is an equidigital number, since it uses as much as digits as its factorization.

21001323853 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 21001323853 its reverse (35832310012), we get a palindrome (56833633865).

The spelling of 21001323853 in words is "twenty-one billion, one million, three hundred twenty-three thousand, eight hundred fifty-three".