1280721 has 8 divisors (see below), whose sum is σ = 1839040. Its totient is φ = 788112.

The previous prime is 1280707. The next prime is 1280737. The reversal of 1280721 is 1270821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1280721 - 2¹⁴ = 1264337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1280761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16381 + ... + 16458.

It is an arithmetic number, because the mean of its divisors is an integer number (229880).

2^1280721 is an apocalyptic number.

It is an amenable number.

1280721 is a deficient number, since it is larger than the sum of its proper divisors (558319).

1280721 is a wasteful number, since it uses less digits than its factorization.

1280721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32855.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 1280721 is about 1131.6894450334. The cubic root of 1280721 is about 108.5970872445.

The spelling of 1280721 in words is "one million, two hundred eighty thousand, seven hundred twenty-one".