1216530500 has 24 divisors (see below), whose sum is σ = 2656903704. Its totient is φ = 486612000.

The previous prime is 1216530493. The next prime is 1216530509. The reversal of 1216530500 is 50356121.

It can be written as a sum of positive squares in 4 ways, for example, as 208975936 + 1007554564 = 14456^2 + 31742^2 .

It is not an unprimeable number, because it can be changed into a prime (1216530509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1216031 + ... + 1217030.

It is an arithmetic number, because the mean of its divisors is an integer number (110704321).

Almost surely, 2^1216530500 is an apocalyptic number.

1216530500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216530500 is an abundant number, since it is smaller than the sum of its proper divisors (1440373204).

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

1216530500 is a wasteful number, since it uses less digits than its factorization.

1216530500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2433080 (or 2433068 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 1216530500 is about 34878.7972843101. The cubic root of 1216530500 is about 1067.5158548031.

Adding to 1216530500 its reverse (50356121), we get a palindrome (1266886621).

The spelling of 1216530500 in words is "one billion, two hundred sixteen million, five hundred thirty thousand, five hundred".