1211947643 has 2 divisors, whose sum is σ = 1211947644. Its totient is φ = 1211947642.

The previous prime is 1211947637. The next prime is 1211947651. The reversal of 1211947643 is 3467491121.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211947643 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1211947597 and 1211947606.

It is not a weakly prime, because it can be changed into another prime (1211947043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605973821 + 605973822.

It is an arithmetic number, because the mean of its divisors is an integer number (605973822).

Almost surely, 2^1211947643 is an apocalyptic number.

1211947643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211947643 is an equidigital number, since it uses as much as digits as its factorization.

1211947643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 1211947643 is about 34813.0384051723. The cubic root of 1211947643 is about 1066.1736693254.

The spelling of 1211947643 in words is "one billion, two hundred eleven million, nine hundred forty-seven thousand, six hundred forty-three".