21589012649 has 2 divisors, whose sum is σ = 21589012650. Its totient is φ = 21589012648.

The previous prime is 21589012607. The next prime is 21589012667. The reversal of 21589012649 is 94621098512.

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., 21589012624 + 25 = 146932^2 + 5^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21589012649 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21589812649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10794506324 + 10794506325.

It is an arithmetic number, because the mean of its divisors is an integer number (10794506325).

Almost surely, 2^21589012649 is an apocalyptic number.

It is an amenable number.

21589012649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21589012649 is an equidigital number, since it uses as much as digits as its factorization.

21589012649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 47.

The spelling of 21589012649 in words is "twenty-one billion, five hundred eighty-nine million, twelve thousand, six hundred forty-nine".