1221211867 has 2 divisors, whose sum is σ = 1221211868. Its totient is φ = 1221211866.

The previous prime is 1221211801. The next prime is 1221211991. The reversal of 1221211867 is 7681121221.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221211867 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221211067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610605933 + 610605934.

It is an arithmetic number, because the mean of its divisors is an integer number (610605934).

Almost surely, 2^1221211867 is an apocalyptic number.

1221211867 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221211867 is an equidigital number, since it uses as much as digits as its factorization.

1221211867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 31.

The square root of 1221211867 is about 34945.8419128800. The cubic root of 1221211867 is about 1068.8834152291.

The spelling of 1221211867 in words is "one billion, two hundred twenty-one million, two hundred eleven thousand, eight hundred sixty-seven".