1216665120 has 192 divisors, whose sum is σ = 4215214080. Its totient is φ = 292531200.

The previous prime is 1216665113. The next prime is 1216665139. The reversal of 1216665120 is 215666121.

It is a super-2 number, since 2×1216665120² = 2960548028449228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 690801 + ... + 692559.

It is an arithmetic number, because the mean of its divisors is an integer number (21954240).

Almost surely, 2^1216665120 is an apocalyptic number.

1216665120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1216665120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2107607040).

1216665120 is an abundant number, since it is smaller than the sum of its proper divisors (2998548960).

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

1216665120 is a wasteful number, since it uses less digits than its factorization.

1216665120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1919 (or 1911 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 1216665120 is about 34880.7270566426. The cubic root of 1216665120 is about 1067.5552300822. Note that the first 3 decimals are identical.

1216665120 divided by its sum of digits (30) gives a palindrome (40555504).

The spelling of 1216665120 in words is "one billion, two hundred sixteen million, six hundred sixty-five thousand, one hundred twenty".