1219891221 has 12 divisors (see below), whose sum is σ = 1809688972. Its totient is φ = 791280576.

The previous prime is 1219891217. The next prime is 1219891223. The reversal of 1219891221 is 1221989121.

It can be written as a sum of positive squares in 2 ways, for example, as 975312900 + 244578321 = 31230^2 + 15639^2 .

It is not a de Polignac number, because 1219891221 - 2² = 1219891217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1219891223) 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 11 ways as a sum of consecutive naturals, for example, 1831336 + ... + 1832001.

Almost surely, 2^1219891221 is an apocalyptic number.

It is an amenable number.

1219891221 is a deficient number, since it is larger than the sum of its proper divisors (589797751).

1219891221 is a wasteful number, since it uses less digits than its factorization.

1219891221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3663380 (or 3663377 counting only the distinct ones).

The product of its digits is 5184, while the sum is 36.

The square root of 1219891221 is about 34926.9411915787. The cubic root of 1219891221 is about 1068.4979713920.

The spelling of 1219891221 in words is "one billion, two hundred nineteen million, eight hundred ninety-one thousand, two hundred twenty-one".