1216521336 has 32 divisors (see below), whose sum is σ = 3173535360. Its totient is φ = 387876192.

The previous prime is 1216521307. The next prime is 1216521337. The reversal of 1216521336 is 6331256121.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216521337) 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 7 ways as a sum of consecutive naturals, for example, 1101370 + ... + 1102473.

It is an arithmetic number, because the mean of its divisors is an integer number (99172980).

Almost surely, 2^1216521336 is an apocalyptic number.

It is an amenable number.

1216521336 is an abundant number, since it is smaller than the sum of its proper divisors (1957014024).

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

1216521336 is a wasteful number, since it uses less digits than its factorization.

1216521336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2203875 (or 2203871 counting only the distinct ones).

The product of its digits is 6480, while the sum is 30.

The square root of 1216521336 is about 34878.6659148540. The cubic root of 1216521336 is about 1067.5131743004.

Adding to 1216521336 its reverse (6331256121), we get a palindrome (7547777457).

The spelling of 1216521336 in words is "one billion, two hundred sixteen million, five hundred twenty-one thousand, three hundred thirty-six".