1221321187 has 2 divisors, whose sum is σ = 1221321188. Its totient is φ = 1221321186.

The previous prime is 1221321169. The next prime is 1221321203. The reversal of 1221321187 is 7811231221.

It is a strong prime.

It is an emirp because it is prime and its reverse (7811231221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221321187 - 2¹¹ = 1221319139 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221321587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610660593 + 610660594.

It is an arithmetic number, because the mean of its divisors is an integer number (610660594).

Almost surely, 2^1221321187 is an apocalyptic number.

1221321187 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221321187 is an equidigital number, since it uses as much as digits as its factorization.

1221321187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1344, while the sum is 28.

The square root of 1221321187 is about 34947.4060124639. The cubic root of 1221321187 is about 1068.9153089165.

The spelling of 1221321187 in words is "one billion, two hundred twenty-one million, three hundred twenty-one thousand, one hundred eighty-seven".