1216636520 has 96 divisors (see below), whose sum is σ = 3122370720. Its totient is φ = 423096960.

The previous prime is 1216636511. The next prime is 1216636523. The reversal of 1216636520 is 256366121.

It is not an unprimeable number, because it can be changed into a prime (1216636523) 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 23 ways as a sum of consecutive naturals, for example, 230147 + ... + 235373.

It is an arithmetic number, because the mean of its divisors is an integer number (32524695).

Almost surely, 2^1216636520 is an apocalyptic number.

1216636520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1216636520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1561185360).

1216636520 is an abundant number, since it is smaller than the sum of its proper divisors (1905734200).

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

1216636520 is a wasteful number, since it uses less digits than its factorization.

1216636520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5295 (or 5268 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 1216636520 is about 34880.3170857147. The cubic root of 1216636520 is about 1067.5468650527.

It can be divided in two parts, 1216 and 636520, that added together give a palindrome (637736).

The spelling of 1216636520 in words is "one billion, two hundred sixteen million, six hundred thirty-six thousand, five hundred twenty".