1211979187 has 2 divisors, whose sum is σ = 1211979188. Its totient is φ = 1211979186.

The previous prime is 1211979173. The next prime is 1211979203. The reversal of 1211979187 is 7819791121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211979187 - 2²³ = 1203590579 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211979137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605989593 + 605989594.

It is an arithmetic number, because the mean of its divisors is an integer number (605989594).

Almost surely, 2^1211979187 is an apocalyptic number.

1211979187 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211979187 is an equidigital number, since it uses as much as digits as its factorization.

1211979187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63504, while the sum is 46.

The square root of 1211979187 is about 34813.4914508729. The cubic root of 1211979187 is about 1066.1829191998.

The spelling of 1211979187 in words is "one billion, two hundred eleven million, nine hundred seventy-nine thousand, one hundred eighty-seven".