1216242720 has 432 divisors, whose sum is σ = 5270323968. Its totient is φ = 252564480.

The previous prime is 1216242701. The next prime is 1216242749. The reversal of 1216242720 is 272426121.

1216242720 is a `hidden beast` number, since 1 + 216 + 2 + 427 + 20 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 775377 + ... + 776943.

It is an arithmetic number, because the mean of its divisors is an integer number (12199824).

Almost surely, 2^1216242720 is an apocalyptic number.

1216242720 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 1216242720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2635161984).

1216242720 is an abundant number, since it is smaller than the sum of its proper divisors (4054081248).

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

1216242720 is a wasteful number, since it uses less digits than its factorization.

1216242720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1613 (or 1595 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 1216242720 is about 34874.6716113571. The cubic root of 1216242720 is about 1067.4316716993.

Adding to 1216242720 its reverse (272426121), we get a palindrome (1488668841).

The spelling of 1216242720 in words is "one billion, two hundred sixteen million, two hundred forty-two thousand, seven hundred twenty".