1211211979 has 2 divisors, whose sum is σ = 1211211980. Its totient is φ = 1211211978.

The previous prime is 1211211977. The next prime is 1211212063. The reversal of 1211211979 is 9791121121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211211979 - 2¹ = 1211211977 is a prime.

Together with 1211211977, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1211211973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605605989 + 605605990.

It is an arithmetic number, because the mean of its divisors is an integer number (605605990).

Almost surely, 2^1211211979 is an apocalyptic number.

1211211979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211211979 is an equidigital number, since it uses as much as digits as its factorization.

1211211979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268, while the sum is 34.

The square root of 1211211979 is about 34802.4708749250. The cubic root of 1211211979 is about 1065.9578997344.

The spelling of 1211211979 in words is "one billion, two hundred eleven million, two hundred eleven thousand, nine hundred seventy-nine".