21253423253 has 2 divisors, whose sum is σ = 21253423254. Its totient is φ = 21253423252.

The previous prime is 21253423249. The next prime is 21253423271. The reversal of 21253423253 is 35232435212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17544856849 + 3708566404 = 132457^2 + 60898^2 .

It is a cyclic number.

It is not a de Polignac number, because 21253423253 - 2² = 21253423249 is a prime.

It is a super-2 number, since 2×21253423253² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21253423283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626711626 + 10626711627.

It is an arithmetic number, because the mean of its divisors is an integer number (10626711627).

Almost surely, 2^21253423253 is an apocalyptic number.

It is an amenable number.

21253423253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21253423253 is an equidigital number, since it uses as much as digits as its factorization.

21253423253 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 32.

Adding to 21253423253 its reverse (35232435212), we get a palindrome (56485858465).

The spelling of 21253423253 in words is "twenty-one billion, two hundred fifty-three million, four hundred twenty-three thousand, two hundred fifty-three".