1216720755900 has 756 divisors, whose sum is σ = 4359510114120. Its totient is φ = 294408691200.

The previous prime is 1216720755781. The next prime is 1216720755917. The reversal of 1216720755900 is 95570276121.

1216720755900 is a `hidden beast` number, since 1 + 21 + 6 + 72 + 0 + 7 + 559 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 251 ways as a sum of consecutive naturals, for example, 751525291 + ... + 751526909.

It is an arithmetic number, because the mean of its divisors is an integer number (5766547770).

Almost surely, 2^{1216720755900} is an apocalyptic number.

1216720755900 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 1216720755900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2179755057060).

1216720755900 is an abundant number, since it is smaller than the sum of its proper divisors (3142789358220).

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

1216720755900 is a wasteful number, since it uses less digits than its factorization.

1216720755900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1738 (or 1703 counting only the distinct ones).

The product of its (nonzero) digits is 264600, while the sum is 45.

The spelling of 1216720755900 in words is "one trillion, two hundred sixteen billion, seven hundred twenty million, seven hundred fifty-five thousand, nine hundred".