21102013253 has 2 divisors, whose sum is σ = 21102013254. Its totient is φ = 21102013252.

The previous prime is 21102013243. The next prime is 21102013307. The reversal of 21102013253 is 35231020112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15221884129 + 5880129124 = 123377^2 + 76682^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102013253 - 2⁴ = 21102013237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102013243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551006626 + 10551006627.

It is an arithmetic number, because the mean of its divisors is an integer number (10551006627).

Almost surely, 2^21102013253 is an apocalyptic number.

It is an amenable number.

21102013253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102013253 is an equidigital number, since it uses as much as digits as its factorization.

21102013253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

Adding to 21102013253 its reverse (35231020112), we get a palindrome (56333033365).

The spelling of 21102013253 in words is "twenty-one billion, one hundred two million, thirteen thousand, two hundred fifty-three".