1216500720 has 80 divisors (see below), whose sum is σ = 3774654240. Its totient is φ = 324099072.

The previous prime is 1216500653. The next prime is 1216500721. The reversal of 1216500720 is 270056121.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216500721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 399042 + ... + 402078.

It is an arithmetic number, because the mean of its divisors is an integer number (47183178).

Almost surely, 2^1216500720 is an apocalyptic number.

1216500720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216500720 is an abundant number, since it is smaller than the sum of its proper divisors (2558153520).

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

1216500720 is a wasteful number, since it uses less digits than its factorization.

1216500720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4722 (or 4716 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 1216500720 is about 34878.3703747753. The cubic root of 1216500720 is about 1067.5071439977.

Adding to 1216500720 its reverse (270056121), we get a palindrome (1486556841).

The spelling of 1216500720 in words is "one billion, two hundred sixteen million, five hundred thousand, seven hundred twenty".