1217655267840 has 480 divisors, whose sum is σ = 4842602107200. Its totient is φ = 279651778560.

The previous prime is 1217655267823. The next prime is 1217655267883. The reversal of 1217655267840 is 487625567121.

It is a happy number.

1217655267840 is a `hidden beast` number, since 1 + 2 + 1 + 7 + 6 + 5 + 526 + 78 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4688926 + ... + 4941794.

It is an arithmetic number, because the mean of its divisors is an integer number (10088754390).

Almost surely, 2^{1217655267840} is an apocalyptic number.

1217655267840 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 1217655267840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2421301053600).

1217655267840 is an abundant number, since it is smaller than the sum of its proper divisors (3624946839360).

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

1217655267840 is a wasteful number, since it uses less digits than its factorization.

1217655267840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252928 (or 252909 counting only the distinct ones).

The product of its (nonzero) digits is 5644800, while the sum is 54.

The spelling of 1217655267840 in words is "one trillion, two hundred seventeen billion, six hundred fifty-five million, two hundred sixty-seven thousand, eight hundred forty".