1221228185 has 16 divisors (see below), whose sum is σ = 1485403920. Its totient is φ = 963747840.

The previous prime is 1221228181. The next prime is 1221228191. The reversal of 1221228185 is 5818221221.

It can be written as a sum of positive squares in 8 ways, for example, as 477466201 + 743761984 = 21851^2 + 27272^2 .

It is not a de Polignac number, because 1221228185 - 2² = 1221228181 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1221228181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 202169 + ... + 208121.

It is an arithmetic number, because the mean of its divisors is an integer number (92837745).

Almost surely, 2^1221228185 is an apocalyptic number.

It is an amenable number.

1221228185 is a deficient number, since it is larger than the sum of its proper divisors (264175735).

1221228185 is an equidigital number, since it uses as much as digits as its factorization.

1221228185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6508.

The product of its digits is 5120, while the sum is 32.

The square root of 1221228185 is about 34946.0753876598. The cubic root of 1221228185 is about 1068.8881760634. Note that the first 3 decimals are identical.

The spelling of 1221228185 in words is "one billion, two hundred twenty-one million, two hundred twenty-eight thousand, one hundred eighty-five".