21243130890197 has 2 divisors, whose sum is σ = 21243130890198. Its totient is φ = 21243130890196.

The previous prime is 21243130890187. The next prime is 21243130890221. The reversal of 21243130890197 is 79109803134212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20817556015876 + 425574874321 = 4562626^2 + 652361^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243130890197 - 2⁸ = 21243130889941 is a prime.

It is a super-2 number, since 2×21243130890197² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243130890187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621565445098 + 10621565445099.

It is an arithmetic number, because the mean of its divisors is an integer number (10621565445099).

Almost surely, 2^{21243130890197} is an apocalyptic number.

It is an amenable number.

21243130890197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243130890197 is an equidigital number, since it uses as much as digits as its factorization.

21243130890197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 653184, while the sum is 50.

The spelling of 21243130890197 in words is "twenty-one trillion, two hundred forty-three billion, one hundred thirty million, eight hundred ninety thousand, one hundred ninety-seven".