1211857939 has 2 divisors, whose sum is σ = 1211857940. Its totient is φ = 1211857938.

The previous prime is 1211857901. The next prime is 1211857961. The reversal of 1211857939 is 9397581121.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211857939 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211857139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605928969 + 605928970.

It is an arithmetic number, because the mean of its divisors is an integer number (605928970).

Almost surely, 2^1211857939 is an apocalyptic number.

1211857939 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211857939 is an equidigital number, since it uses as much as digits as its factorization.

1211857939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 46.

The square root of 1211857939 is about 34811.7500134653. The cubic root of 1211857939 is about 1066.1473638979.

The spelling of 1211857939 in words is "one billion, two hundred eleven million, eight hundred fifty-seven thousand, nine hundred thirty-nine".