1216364544 has 180 divisors, whose sum is σ = 3593491356. Its totient is φ = 396361728.

The previous prime is 1216364543. The next prime is 1216364549. The reversal of 1216364544 is 4454636121.

1216364544 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 3 + 645 + 4 + 4 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 272646144 + 943718400 = 16512^2 + 30720^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1216364499 and 1216364508.

It is not an unprimeable number, because it can be changed into a prime (1216364543) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10764232 + ... + 10764344.

Almost surely, 2^1216364544 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1216364544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1796745678).

1216364544 is an abundant number, since it is smaller than the sum of its proper divisors (2377126812).

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

1216364544 is an equidigital number, since it uses as much as digits as its factorization.

1216364544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 191 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 1216364544 is about 34876.4181647141. The cubic root of 1216364544 is about 1067.4673099954.

The spelling of 1216364544 in words is "one billion, two hundred sixteen million, three hundred sixty-four thousand, five hundred forty-four".