21434204353 has 2 divisors, whose sum is σ = 21434204354. Its totient is φ = 21434204352.

The previous prime is 21434204329. The next prime is 21434204371. The reversal of 21434204353 is 35340243412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18480499249 + 2953705104 = 135943^2 + 54348^2 .

It is a cyclic number.

It is not a de Polignac number, because 21434204353 - 2²¹ = 21432107201 is a prime.

It is not a weakly prime, because it can be changed into another prime (21434204383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717102176 + 10717102177.

It is an arithmetic number, because the mean of its divisors is an integer number (10717102177).

Almost surely, 2^21434204353 is an apocalyptic number.

It is an amenable number.

21434204353 is a deficient number, since it is larger than the sum of its proper divisors (1).

21434204353 is an equidigital number, since it uses as much as digits as its factorization.

21434204353 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 31.

Adding to 21434204353 its reverse (35340243412), we get a palindrome (56774447765).

The spelling of 21434204353 in words is "twenty-one billion, four hundred thirty-four million, two hundred four thousand, three hundred fifty-three".