1216625664 has 176 divisors, whose sum is σ = 3447606528. Its totient is φ = 380633088.

The previous prime is 1216625629. The next prime is 1216625681. The reversal of 1216625664 is 4665266121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4733824 + ... + 4734080.

Almost surely, 2^1216625664 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 1216625664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1723803264).

1216625664 is an abundant number, since it is smaller than the sum of its proper divisors (2230980864).

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

1216625664 is a wasteful number, since it uses less digits than its factorization.

1216625664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370 (or 352 counting only the distinct ones).

The product of its digits is 103680, while the sum is 39.

The square root of 1216625664 is about 34880.1614675162. The cubic root of 1216625664 is about 1067.5436898170.

The spelling of 1216625664 in words is "one billion, two hundred sixteen million, six hundred twenty-five thousand, six hundred sixty-four".