21243410897 has 2 divisors, whose sum is σ = 21243410898. Its totient is φ = 21243410896.

The previous prime is 21243410879. The next prime is 21243410899. The reversal of 21243410897 is 79801434212.

Together with previous prime (21243410879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13014018241 + 8229392656 = 114079^2 + 90716^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243410897 - 2²⁶ = 21176302033 is a prime.

Together with 21243410899, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21243410899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621705448 + 10621705449.

It is an arithmetic number, because the mean of its divisors is an integer number (10621705449).

Almost surely, 2^21243410897 is an apocalyptic number.

It is an amenable number.

21243410897 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243410897 is an equidigital number, since it uses as much as digits as its factorization.

21243410897 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96768, while the sum is 41.

The spelling of 21243410897 in words is "twenty-one billion, two hundred forty-three million, four hundred ten thousand, eight hundred ninety-seven".