21500322253 has 2 divisors, whose sum is σ = 21500322254. Its totient is φ = 21500322252.

The previous prime is 21500322197. The next prime is 21500322257. The reversal of 21500322253 is 35222300512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20735136009 + 765186244 = 143997^2 + 27662^2 .

It is a cyclic number.

It is not a de Polignac number, because 21500322253 - 2²⁵ = 21466767821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21500322257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10750161126 + 10750161127.

It is an arithmetic number, because the mean of its divisors is an integer number (10750161127).

Almost surely, 2^21500322253 is an apocalyptic number.

It is an amenable number.

21500322253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21500322253 is an equidigital number, since it uses as much as digits as its factorization.

21500322253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 25.

Adding to 21500322253 its reverse (35222300512), we get a palindrome (56722622765).

The spelling of 21500322253 in words is "twenty-one billion, five hundred million, three hundred twenty-two thousand, two hundred fifty-three".