1216891384384 has 63 divisors (see below), whose sum is σ = 2615055403737. Its totient is φ = 561589227264.

The previous prime is 1216891384381. The next prime is 1216891384393. The reversal of 1216891384384 is 4834831986121.

The square root of 1216891384384 is 1103128.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 180013518400 + 1036877865984 = 424280^2 + 1018272^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216891384381) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 114720009 + ... + 114730615.

Almost surely, 2^{1216891384384} is an apocalyptic number.

1216891384384 is the 1103128-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1216891384384

1216891384384 is an abundant number, since it is smaller than the sum of its proper divisors (1398164019353).

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

1216891384384 is an frugal number, since it uses more digits than its factorization.

1216891384384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21252 (or 10622 counting only the distinct ones).

The product of its digits is 7962624, while the sum is 58.

The spelling of 1216891384384 in words is "one trillion, two hundred sixteen billion, eight hundred ninety-one million, three hundred eighty-four thousand, three hundred eighty-four".