1221321247 has 2 divisors, whose sum is σ = 1221321248. Its totient is φ = 1221321246.

The previous prime is 1221321239. The next prime is 1221321331. The reversal of 1221321247 is 7421231221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221321247 - 2³ = 1221321239 is a prime.

It is a super-3 number, since 3×1221321247³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221321547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610660623 + 610660624.

It is an arithmetic number, because the mean of its divisors is an integer number (610660624).

Almost surely, 2^1221321247 is an apocalyptic number.

1221321247 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221321247 is an equidigital number, since it uses as much as digits as its factorization.

1221321247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1344, while the sum is 25.

The square root of 1221321247 is about 34947.4068708967. The cubic root of 1221321247 is about 1068.9153264207.

Adding to 1221321247 its reverse (7421231221), we get a palindrome (8642552468).

The spelling of 1221321247 in words is "one billion, two hundred twenty-one million, three hundred twenty-one thousand, two hundred forty-seven".