21123310253 has 2 divisors, whose sum is σ = 21123310254. Its totient is φ = 21123310252.

The previous prime is 21123310199. The next prime is 21123310283. The reversal of 21123310253 is 35201332112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15434832169 + 5688478084 = 124237^2 + 75422^2 .

It is a cyclic number.

It is not a de Polignac number, because 21123310253 - 2⁸ = 21123309997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123310283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561655126 + 10561655127.

It is an arithmetic number, because the mean of its divisors is an integer number (10561655127).

Almost surely, 2^21123310253 is an apocalyptic number.

It is an amenable number.

21123310253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123310253 is an equidigital number, since it uses as much as digits as its factorization.

21123310253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 23.

Adding to 21123310253 its reverse (35201332112), we get a palindrome (56324642365).

The spelling of 21123310253 in words is "twenty-one billion, one hundred twenty-three million, three hundred ten thousand, two hundred fifty-three".