1263821969 has 2 divisors, whose sum is σ = 1263821970. Its totient is φ = 1263821968.

The previous prime is 1263821957. The next prime is 1263821971. The reversal of 1263821969 is 9691283621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 905287744 + 358534225 = 30088^2 + 18935^2 .

It is a cyclic number.

It is not a de Polignac number, because 1263821969 - 2²⁴ = 1247044753 is a prime.

It is a super-2 number, since 2×1263821969² = 3194491938654073922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1263821971, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1263829969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631910984 + 631910985.

It is an arithmetic number, because the mean of its divisors is an integer number (631910985).

Almost surely, 2^1263821969 is an apocalyptic number.

It is an amenable number.

1263821969 is a deficient number, since it is larger than the sum of its proper divisors (1).

1263821969 is an equidigital number, since it uses as much as digits as its factorization.

1263821969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 47.

The square root of 1263821969 is about 35550.2738245432. The cubic root of 1263821969 is about 1081.1732702676.

The spelling of 1263821969 in words is "one billion, two hundred sixty-three million, eight hundred twenty-one thousand, nine hundred sixty-nine".