1221075305 has 8 divisors (see below), whose sum is σ = 1515817800. Its totient is φ = 943175296.

The previous prime is 1221075281. The next prime is 1221075311. The reversal of 1221075305 is 5035701221.

It can be written as a sum of positive squares in 4 ways, for example, as 310182544 + 910892761 = 17612^2 + 30181^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221075305 - 2¹⁸ = 1220813161 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4210460 + ... + 4210749.

It is an arithmetic number, because the mean of its divisors is an integer number (189477225).

Almost surely, 2^1221075305 is an apocalyptic number.

It is an amenable number.

1221075305 is a deficient number, since it is larger than the sum of its proper divisors (294742495).

1221075305 is an equidigital number, since it uses as much as digits as its factorization.

1221075305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8421243.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 1221075305 is about 34943.8879491106. The cubic root of 1221075305 is about 1068.8435711196.

Adding to 1221075305 its reverse (5035701221), we get a palindrome (6256776526).

The spelling of 1221075305 in words is "one billion, two hundred twenty-one million, seventy-five thousand, three hundred five".