1221680 has 20 divisors (see below), whose sum is σ = 2840592. Its totient is φ = 488640.

The previous prime is 1221667. The next prime is 1221707. The reversal of 1221680 is 861221.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 7556 + ... + 7715.

2^1221680 is an apocalyptic number.

1221680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221680 is an abundant number, since it is smaller than the sum of its proper divisors (1618912).

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

1221680 is a wasteful number, since it uses less digits than its factorization.

1221680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15284 (or 15278 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 1221680 is about 1105.2963403540. The cubic root of 1221680 is about 106.9019977849.

The spelling of 1221680 in words is "one million, two hundred twenty-one thousand, six hundred eighty".