1217204640 has 144 divisors (see below), whose sum is σ = 4166443008. Its totient is φ = 323593728.

The previous prime is 1217204629. The next prime is 1217204647. The reversal of 1217204640 is 464027121.

1217204640 is a `hidden beast` number, since 1 + 2 + 17 + 2 + 0 + 4 + 640 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (1217204647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 550417 + ... + 552623.

It is an arithmetic number, because the mean of its divisors is an integer number (28933632).

Almost surely, 2^1217204640 is an apocalyptic number.

1217204640 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 1217204640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2083221504).

1217204640 is an abundant number, since it is smaller than the sum of its proper divisors (2949238368).

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

1217204640 is a wasteful number, since it uses less digits than its factorization.

1217204640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2611 (or 2600 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 1217204640 is about 34888.4599832093. The cubic root of 1217204640 is about 1067.7130062506.

The spelling of 1217204640 in words is "one billion, two hundred seventeen million, two hundred four thousand, six hundred forty".