21243263669 has 2 divisors, whose sum is σ = 21243263670. Its totient is φ = 21243263668.

The previous prime is 21243263647. The next prime is 21243263689. The reversal of 21243263669 is 96636234212.

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., 16802640625 + 4440623044 = 129625^2 + 66638^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243263669 - 2⁸ = 21243263413 is a prime.

It is a super-2 number, since 2×21243263669² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243263689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621631834 + 10621631835.

It is an arithmetic number, because the mean of its divisors is an integer number (10621631835).

Almost surely, 2^21243263669 is an apocalyptic number.

It is an amenable number.

21243263669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243263669 is an equidigital number, since it uses as much as digits as its factorization.

21243263669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872, while the sum is 44.

The spelling of 21243263669 in words is "twenty-one billion, two hundred forty-three million, two hundred sixty-three thousand, six hundred sixty-nine".