21253222447 has 2 divisors, whose sum is σ = 21253222448. Its totient is φ = 21253222446.

The previous prime is 21253222423. The next prime is 21253222453. The reversal of 21253222447 is 74422235212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21253222447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21253222457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626611223 + 10626611224.

It is an arithmetic number, because the mean of its divisors is an integer number (10626611224).

Almost surely, 2^21253222447 is an apocalyptic number.

21253222447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21253222447 is an equidigital number, since it uses as much as digits as its factorization.

21253222447 is an evil number, because the sum of its binary digits is even.

The product of its digits is 53760, while the sum is 34.

Adding to 21253222447 its reverse (74422235212), we get a palindrome (95675457659).

The spelling of 21253222447 in words is "twenty-one billion, two hundred fifty-three million, two hundred twenty-two thousand, four hundred forty-seven".