1216596820 has 12 divisors (see below), whose sum is σ = 2554853364. Its totient is φ = 486638720.

The previous prime is 1216596817. The next prime is 1216596827. The reversal of 1216596820 is 286956121.

It can be written as a sum of positive squares in 2 ways, for example, as 216266436 + 1000330384 = 14706^2 + 31628^2 .

It is a super-2 number, since 2×1216596820² = 2960215644868224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216596827) 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 3 ways as a sum of consecutive naturals, for example, 30414901 + ... + 30414940.

It is an arithmetic number, because the mean of its divisors is an integer number (212904447).

Almost surely, 2^1216596820 is an apocalyptic number.

1216596820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216596820 is an abundant number, since it is smaller than the sum of its proper divisors (1338256544).

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

1216596820 is a wasteful number, since it uses less digits than its factorization.

1216596820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60829850 (or 60829848 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 1216596820 is about 34879.7479922089. The cubic root of 1216596820 is about 1067.5352532385.

The spelling of 1216596820 in words is "one billion, two hundred sixteen million, five hundred ninety-six thousand, eight hundred twenty".