1216621588 has 54 divisors (see below), whose sum is σ = 2671074378. Its totient is φ = 480604320.

The previous prime is 1216621583. The next prime is 1216621589. The reversal of 1216621588 is 8851266121.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 842276484 + 374345104 = 29022^2 + 19348^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1216621588.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216621583) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1760323 + ... + 1761013.

Almost surely, 2^1216621588 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 1216621588, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1335537189).

1216621588 is an abundant number, since it is smaller than the sum of its proper divisors (1454452790).

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

1216621588 is an equidigital number, since it uses as much as digits as its factorization.

1216621588 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1413 (or 713 counting only the distinct ones).

The product of its digits is 46080, while the sum is 40.

The square root of 1216621588 is about 34880.1030388386. The cubic root of 1216621588 is about 1067.5424976363.

The spelling of 1216621588 in words is "one billion, two hundred sixteen million, six hundred twenty-one thousand, five hundred eighty-eight".