1221857512 has 16 divisors (see below), whose sum is σ = 2352901860. Its totient is φ = 594417024.

The previous prime is 1221857509. The next prime is 1221857519. The reversal of 1221857512 is 2157581221.

It can be written as a sum of positive squares in 2 ways, for example, as 1138792516 + 83064996 = 33746^2 + 9114^2 .

It is not an unprimeable number, because it can be changed into a prime (1221857519) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2063653 + ... + 2064244.

Almost surely, 2^1221857512 is an apocalyptic number.

It is an amenable number.

1221857512 is a deficient number, since it is larger than the sum of its proper divisors (1131044348).

1221857512 is a wasteful number, since it uses less digits than its factorization.

1221857512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4127940 (or 4127936 counting only the distinct ones).

The product of its digits is 11200, while the sum is 34.

The square root of 1221857512 is about 34955.0784865375. The cubic root of 1221857512 is about 1069.0717520954.

The spelling of 1221857512 in words is "one billion, two hundred twenty-one million, eight hundred fifty-seven thousand, five hundred twelve".