1217135520 has 144 divisors (see below), whose sum is σ = 4200585480. Its totient is φ = 320888832.

The previous prime is 1217135477. The next prime is 1217135581. The reversal of 1217135520 is 255317121.

1217135520 is a `hidden beast` number, since 1 + 2 + 1 + 7 + 135 + 520 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 454712976 + 762422544 = 21324^2 + 27612^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123412 + ... + 132908.

Almost surely, 2^1217135520 is an apocalyptic number.

1217135520 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 1217135520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2100292740).

1217135520 is an abundant number, since it is smaller than the sum of its proper divisors (2983449960).

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

1217135520 is a wasteful number, since it uses less digits than its factorization.

1217135520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9607 (or 9596 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 1217135520 is about 34887.4693837200. The cubic root of 1217135520 is about 1067.6927955379.

The spelling of 1217135520 in words is "one billion, two hundred seventeen million, one hundred thirty-five thousand, five hundred twenty".