1221019985 has 32 divisors (see below), whose sum is σ = 1572372000. Its totient is φ = 907038720.

The previous prime is 1221019979. The next prime is 1221020069. The reversal of 1221019985 is 5899101221.

It is a happy number.

It can be written as a sum of positive squares in 16 ways, for example, as 426174736 + 794845249 = 20644^2 + 28193^2 .

It is not a de Polignac number, because 1221019985 - 2¹⁰ = 1221018961 is a prime.

It is an unprimeable number.

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 in 31 ways as a sum of consecutive naturals, for example, 2900075 + ... + 2900495.

It is an arithmetic number, because the mean of its divisors is an integer number (49136625).

Almost surely, 2^1221019985 is an apocalyptic number.

It is an amenable number.

1221019985 is a deficient number, since it is larger than the sum of its proper divisors (351352015).

1221019985 is a wasteful number, since it uses less digits than its factorization.

1221019985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 821.

The product of its (nonzero) digits is 12960, while the sum is 38.

The square root of 1221019985 is about 34943.0963854092. The cubic root of 1221019985 is about 1068.8274297948.

The spelling of 1221019985 in words is "one billion, two hundred twenty-one million, nineteen thousand, nine hundred eighty-five".