21226536662197 has 2 divisors, whose sum is σ = 21226536662198. Its totient is φ = 21226536662196.

The previous prime is 21226536662143. The next prime is 21226536662207. The reversal of 21226536662197 is 79126663562212.

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., 20840996257636 + 385540404561 = 4565194^2 + 620919^2 .

It is a cyclic number.

It is not a de Polignac number, because 21226536662197 - 2¹¹ = 21226536660149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21226536662137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613268331098 + 10613268331099.

It is an arithmetic number, because the mean of its divisors is an integer number (10613268331099).

Almost surely, 2^{21226536662197} is an apocalyptic number.

It is an amenable number.

21226536662197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21226536662197 is an equidigital number, since it uses as much as digits as its factorization.

21226536662197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19595520, while the sum is 58.

The spelling of 21226536662197 in words is "twenty-one trillion, two hundred twenty-six billion, five hundred thirty-six million, six hundred sixty-two thousand, one hundred ninety-seven".