21035384221 has 2 divisors, whose sum is σ = 21035384222. Its totient is φ = 21035384220.

The previous prime is 21035384213. The next prime is 21035384261. The reversal of 21035384221 is 12248353012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19958625625 + 1076758596 = 141275^2 + 32814^2 .

It is a cyclic number.

It is not a de Polignac number, because 21035384221 - 2³ = 21035384213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21035384261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10517692110 + 10517692111.

It is an arithmetic number, because the mean of its divisors is an integer number (10517692111).

Almost surely, 2^21035384221 is an apocalyptic number.

It is an amenable number.

21035384221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21035384221 is an equidigital number, since it uses as much as digits as its factorization.

21035384221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 31.

The spelling of 21035384221 in words is "twenty-one billion, thirty-five million, three hundred eighty-four thousand, two hundred twenty-one".