1216708720 has 40 divisors (see below), whose sum is σ = 2831778576. Its totient is φ = 486179328.

The previous prime is 1216708657. The next prime is 1216708723. The reversal of 1216708720 is 278076121.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216708723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75279 + ... + 90001.

Almost surely, 2^1216708720 is an apocalyptic number.

1216708720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216708720 is an abundant number, since it is smaller than the sum of its proper divisors (1615069856).

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

1216708720 is a wasteful number, since it uses less digits than its factorization.

1216708720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15769 (or 15763 counting only the distinct ones).

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 1216708720 is about 34881.3520380160. The cubic root of 1216708720 is about 1067.5679821127.

The spelling of 1216708720 in words is "one billion, two hundred sixteen million, seven hundred eight thousand, seven hundred twenty".