1221255437 has 2 divisors, whose sum is σ = 1221255438. Its totient is φ = 1221255436.

The previous prime is 1221255383. The next prime is 1221255463. The reversal of 1221255437 is 7345521221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 796029796 + 425225641 = 28214^2 + 20621^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221255437 - 2²⁴ = 1204478221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221255467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610627718 + 610627719.

It is an arithmetic number, because the mean of its divisors is an integer number (610627719).

Almost surely, 2^1221255437 is an apocalyptic number.

It is an amenable number.

1221255437 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221255437 is an equidigital number, since it uses as much as digits as its factorization.

1221255437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16800, while the sum is 32.

The square root of 1221255437 is about 34946.4653005136. The cubic root of 1221255437 is about 1068.8961268363.

Adding to 1221255437 its reverse (7345521221), we get a palindrome (8566776658).

The spelling of 1221255437 in words is "one billion, two hundred twenty-one million, two hundred fifty-five thousand, four hundred thirty-seven".