1280021 has 8 divisors (see below), whose sum is σ = 1334784. Its totient is φ = 1226160.

The previous prime is 1279997. The next prime is 1280023. The reversal of 1280021 is 1200821.

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

It is a cyclic number.

It is not a de Polignac number, because 1280021 - 2¹⁰ = 1278997 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1279978 and 1280005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1280023) 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, 4736 + ... + 4998.

It is an arithmetic number, because the mean of its divisors is an integer number (166848).

2^1280021 is an apocalyptic number.

It is an amenable number.

1280021 is a deficient number, since it is larger than the sum of its proper divisors (54763).

1280021 is a wasteful number, since it uses less digits than its factorization.

1280021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 1280021 is about 1131.3801306369. The cubic root of 1280021 is about 108.5772984394.

Adding to 1280021 its reverse (1200821), we get a palindrome (2480842).

It can be divided in two parts, 12800 and 21, that added together give a palindrome (12821).

The spelling of 1280021 in words is "one million, two hundred eighty thousand, twenty-one".