1221799216 has 40 divisors (see below), whose sum is σ = 2637402624. Its totient is φ = 543543360.

The previous prime is 1221799211. The next prime is 1221799247. The reversal of 1221799216 is 6129971221.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1221799211) 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 in 7 ways as a sum of consecutive naturals, for example, 65580 + ... + 82123.

Almost surely, 2^1221799216 is an apocalyptic number.

1221799216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1221799216 is an abundant number, since it is smaller than the sum of its proper divisors (1415603408).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221799216 is a wasteful number, since it uses less digits than its factorization.

1221799216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147769 (or 147763 counting only the distinct ones).

The product of its digits is 27216, while the sum is 40.

The square root of 1221799216 is about 34954.2446063422. The cubic root of 1221799216 is about 1069.0547496770.

The spelling of 1221799216 in words is "one billion, two hundred twenty-one million, seven hundred ninety-nine thousand, two hundred sixteen".