1243685999 has 2 divisors, whose sum is σ = 1243686000. Its totient is φ = 1243685998.

The previous prime is 1243685977. The next prime is 1243686001. The reversal of 1243685999 is 9995863421.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1243685999 is a prime.

Together with 1243686001, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1243685929) 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, 621842999 + 621843000.

It is an arithmetic number, because the mean of its divisors is an integer number (621843000).

Almost surely, 2^1243685999 is an apocalyptic number.

1243685999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243685999 is an equidigital number, since it uses as much as digits as its factorization.

1243685999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4199040, while the sum is 56.

The square root of 1243685999 is about 35265.9325553713. The cubic root of 1243685999 is about 1075.4005355120.

The spelling of 1243685999 in words is "one billion, two hundred forty-three million, six hundred eighty-five thousand, nine hundred ninety-nine".