21243000240989 has 2 divisors, whose sum is σ = 21243000240990. Its totient is φ = 21243000240988.

The previous prime is 21243000240949. The next prime is 21243000241019. The reversal of 21243000240989 is 98904200034212.

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., 17753792925625 + 3489207315364 = 4213525^2 + 1867942^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243000240989 - 2³² = 21238705273693 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243000240949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621500120494 + 10621500120495.

It is an arithmetic number, because the mean of its divisors is an integer number (10621500120495).

Almost surely, 2^{21243000240989} is an apocalyptic number.

It is an amenable number.

21243000240989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243000240989 is an equidigital number, since it uses as much as digits as its factorization.

21243000240989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 44.

The spelling of 21243000240989 in words is "twenty-one trillion, two hundred forty-three billion, two hundred forty thousand, nine hundred eighty-nine".