21545330689 has 2 divisors, whose sum is σ = 21545330690. Its totient is φ = 21545330688.

The previous prime is 21545330627. The next prime is 21545330699. The reversal of 21545330689 is 98603354512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21170250000 + 375080689 = 145500^2 + 19367^2 .

It is a cyclic number.

It is not a de Polignac number, because 21545330689 - 2¹³ = 21545322497 is a prime.

It is not a weakly prime, because it can be changed into another prime (21545330699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10772665344 + 10772665345.

It is an arithmetic number, because the mean of its divisors is an integer number (10772665345).

Almost surely, 2^21545330689 is an apocalyptic number.

It is an amenable number.

21545330689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21545330689 is an equidigital number, since it uses as much as digits as its factorization.

21545330689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 777600, while the sum is 46.

The spelling of 21545330689 in words is "twenty-one billion, five hundred forty-five million, three hundred thirty thousand, six hundred eighty-nine".