21335724989 has 2 divisors, whose sum is σ = 21335724990. Its totient is φ = 21335724988.

The previous prime is 21335724979. The next prime is 21335725001. The reversal of 21335724989 is 98942753312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11913722500 + 9422002489 = 109150^2 + 97067^2 .

It is a cyclic number.

It is not a de Polignac number, because 21335724989 - 2⁴ = 21335724973 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21335724989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21335724979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10667862494 + 10667862495.

It is an arithmetic number, because the mean of its divisors is an integer number (10667862495).

Almost surely, 2^21335724989 is an apocalyptic number.

It is an amenable number.

21335724989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21335724989 is an equidigital number, since it uses as much as digits as its factorization.

21335724989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3265920, while the sum is 53.

The spelling of 21335724989 in words is "twenty-one billion, three hundred thirty-five million, seven hundred twenty-four thousand, nine hundred eighty-nine".