1217920 has 64 divisors (see below), whose sum is σ = 3194640. Its totient is φ = 440320.

The previous prime is 1217917. The next prime is 1217921. The reversal of 1217920 is 297121.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 1217891 and 1217900.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1217921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6954 + ... + 7126.

2^1217920 is an apocalyptic number.

1217920 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 1217920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1597320).

1217920 is an abundant number, since it is smaller than the sum of its proper divisors (1976720).

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

1217920 is a wasteful number, since it uses less digits than its factorization.

1217920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 22.

The square root of 1217920 is about 1103.5941282917. The cubic root of 1217920 is about 106.7922132848.

The spelling of 1217920 in words is "one million, two hundred seventeen thousand, nine hundred twenty".